What to buy at each stage, what it costs, and what to skip. Written by people who have built these stacks, not analysts who have read about them.
Rees Bayba
Founder, Astra GTM
TL;DR
The B2B outbound tech stack has six layers. Each layer serves a specific function in the pipeline. You can run a functional outbound program with just three of them (data, infrastructure, sequencing). You add the others as your volume and complexity grow. This guide covers what to buy at each stage, what it actually costs, and which tools at each tier are worth the money.
Data is where most outbound programs fail. Bad targeting produces bad results regardless of how good your copy or infrastructure is. This layer handles finding companies, identifying contacts, and enriching both with the signals that make personalization possible.
| Tier | Tools | Monthly cost | What you get |
|---|---|---|---|
| Starter | Apollo free tier + LinkedIn Sales Navigator | $100/mo (Nav only) | 20M+ company records, 270M contacts, basic search filters, 50 email exports/month on Apollo free |
| Growth | Clay + Apollo + ZoomInfo or Cognism | $800-2,500/mo | Full enrichment pipeline, AI-powered research columns (Claygent), multi-provider email waterfall, intent signals |
| Scale | Clay + waterfall (Blitz, LeadMagic, FullEnrich) + Bombora or G2 intent | $3,000-6,000/mo | 300+ concurrent enrichment workers, full provider waterfall, account-level purchase intent data |
Clay is the pivot point between the starter and growth tiers. It is not a data provider -- it is an enrichment orchestration layer that connects every data provider you already use. When you add Clay, you stop buying data and start building a system that finds the right data at the right time. The learning curve is real (plan for 2-4 weeks to build your first solid table), but it is the highest-leverage tool in the modern outbound stack.
On the data provider question: Apollo is the best value for SMB and mid-market contacts. ZoomInfo has better coverage for enterprise accounts and direct dials but costs 5-10x more. Cognism is stronger for European markets and includes GDPR-compliant mobile numbers. Lusha is a good point solution for quick lookups. Most growth-stage teams use Apollo as primary with Clay pulling from multiple providers on misses.
Email infrastructure is the most underinvested layer in most outbound stacks. Teams buy the sequencing tool first and think about infrastructure last. The reality: your deliverability ceiling is set by your infrastructure, and no amount of good copy recovers a burned domain.
| Tier | Tools | Monthly cost | Sending capacity |
|---|---|---|---|
| Starter | Google Workspace domains + Instantly or SmartLead built-in warmup | $6-12/mailbox/mo + sequencer cost | 3-5 domains, 9-15 mailboxes, 270-450 sends/day |
| Growth | Mix of Google + Microsoft domains + Mailforge for managed infrastructure | $500-1,500/mo all-in | 15-25 domains, 45-75 mailboxes, 1,350-2,250 sends/day |
| Scale | Infraforge (dedicated IPs) + multi-provider sending (Google + Microsoft + private SMTP) | $2,000-5,000/mo | 50+ domains, 150+ mailboxes, 4,500+ sends/day with full IP reputation control |
Infrastructure rules that apply at every tier: no domain should send more than 30-40 cold emails per day. Warmup minimum is 14 days before any cold send, 21 days for new domains. Run warmup continuously alongside campaigns -- do not turn it off once you hit your target volume. Rotate domains every 2-3 months and keep retired domains in warmup for potential reuse.
Mailforge (from Instantly) is the cleanest managed infrastructure option for growth-stage teams who do not want to manage domain purchasing, DNS configuration, and warmup manually. Infraforge gives dedicated IP addresses for scale-stage operations where you need full control over IP reputation. Both are significantly less work than managing Google Workspace accounts manually across 50 domains.
The sequencing layer is where your copy lives and your sends are orchestrated. This is the most visible layer -- it is what most people mean when they say 'outbound tool' -- but it is only as good as the layers underneath it.
| Tier | Tools | Monthly cost | Best for |
|---|---|---|---|
| Starter | Instantly ($37/mo) or SmartLead ($39/mo) | $37-39/mo | Email-only sequences, simple A/B testing, solo operators or small teams |
| Growth | Lemlist ($99-159/mo) or SmartLead ($94/mo agency) | $94-159/mo | Multichannel (email + LinkedIn + calling), agency-style client management, advanced personalization |
| Scale | Outreach or SalesLoft (enterprise) or SmartLead at volume | $1,000-4,000/mo | Salesforce-native, enterprise compliance requirements, team-level reporting, AI coaching features |
Instantly vs SmartLead at the starter tier: both are excellent. Instantly has a cleaner UI and better warmup infrastructure built-in. SmartLead has better analytics and a more flexible agency model if you are managing multiple clients. Pick Instantly if you want simplicity; pick SmartLead if you want data.
Lemlist at the growth tier is the best option for multichannel sequences that include LinkedIn touchpoints. Their LinkedIn automation (connect requests, profile views, message sends) is the most reliable in the category. If you are doing email-only sequences, SmartLead at the growth tier has better deliverability controls and more granular analytics.
Outreach and SalesLoft at the scale tier are only worth the cost if you have a large sales team (10+ reps), a Salesforce-native workflow requirement, or enterprise compliance requirements. The per-seat pricing is steep. Most companies at 10-50 employees are better served by SmartLead at scale than by enterprise sequencers.
The CRM is where pipeline lives and where attribution happens. The most common mistake: overbuilding CRM too early. HubSpot free handles 90% of what a 5-10 person sales team needs.
| Tier | Tools | Monthly cost | Best for |
|---|---|---|---|
| Starter | HubSpot free | $0 | Contact tracking, deal management, basic pipeline view, Gmail integration |
| Growth | HubSpot Starter/Professional or Pipedrive | $50-800/mo | Sequence integration, custom properties, reporting, workflow automation |
| Scale | Salesforce Sales Cloud or HubSpot Enterprise | $1,500-5,000/mo | Enterprise data model, advanced custom objects, territory management, revenue forecasting |
HubSpot vs Salesforce: HubSpot is easier to implement, faster to customize, and has better native integrations with modern outbound tools (Clay, Instantly, Lemlist all have first-party HubSpot connectors). Salesforce is necessary when you have complex custom objects, enterprise territory management requirements, or when your buyers specifically require Salesforce as part of a vendor evaluation. Default to HubSpot unless a specific requirement forces Salesforce.
Signal and intent data tells you which accounts are active in the market right now. It is the difference between reaching out when someone is actively evaluating your category versus reaching out randomly. This layer has the highest ROI per dollar at the growth stage -- but only after the first three layers are running.
| Tier | Tools | Monthly cost | Signal types |
|---|---|---|---|
| Starter | LinkedIn job change alerts (free) + Crunchbase funding data (free) | $0-29/mo | Job changes, funding rounds, company news (manual monitoring) |
| Growth | G2 Buyer Intent or Bombora Company Surge | $1,000-3,000/mo | Category research intent (people actively searching for tools like yours), review page visits |
| Scale | 6sense or Demandbase full ABM suite | $3,000-10,000+/mo | Predictive account scoring, anonymous visitor identification, full funnel account intelligence |
G2 Buyer Intent is the highest ROI signal tool for growth-stage B2B companies. If your category has significant review activity on G2, you can reach out to companies that are actively researching you or your competitors right now. Close rates on G2 intent-sourced pipeline are 3-5x higher than cold outbound to unqualified lists. It is the closest thing to warm outbound the market offers.
6sense and Demandbase are genuine value-add at the scale tier but hard to justify below $5M in revenue. Their primary advantage is anonymous visitor de-anonymization (identifying which companies visited your website without filling out a form) and predictive scoring based on buying stage. Wait until you have enough pipeline to measure the ROI before investing.
Most starter-stage teams skip calling entirely and should. Phone adds complexity and cost without proportional return until your list size and deal size justify it. At the growth stage, calling becomes a genuine accelerant for accounts that have already received email touches.
| Tier | Tools | Monthly cost | Best for |
|---|---|---|---|
| Starter | None needed | $0 | Focus on email. Phone before list quality is established wastes effort. |
| Growth | Kixie ($35-95/user/mo) or Lemlist built-in calling | $35-285/mo | Power dialer, voicemail drop, local presence dialing, CRM auto-logging |
| Scale | Nooks or Orum (AI parallel dialers) | $1,000-3,000+/mo | AI parallel dialing (6-8 simultaneous calls), skip voicemail, live conversation detection, coaching |
Nooks and Orum at the scale tier represent the current state of the art in outbound calling. They use AI to dial multiple numbers simultaneously, detect when a live person answers, and connect the SDR instantly. Call volume goes from 40-50 dials per hour (manual) to 200+ per hour. The ROI math only works when you have a large enough calling list and a deal size that justifies SDR time on phone.
| Tier | Monthly cost | Team size | Expected output |
|---|---|---|---|
| Starter | $300-600/mo | 1-2 people | 300-500 sequences/month, 3-8 meetings/month |
| Growth | $2,000-5,000/mo | 2-5 people | 2,000-5,000 sequences/month, 15-40 meetings/month |
| Scale | $8,000-20,000/mo | 5-20 people | 10,000+ sequences/month, 60-150 meetings/month |
This includes Clay, Apollo, email infrastructure (Mailforge), SmartLead or Lemlist, HubSpot Professional, and G2 intent data. Excludes SDR salary. At this spend level, one booked meeting per week per SDR covering costs is a reasonable target.
The most important thing about stack costs: they compound with quality. A $5,000/month stack run by a skilled operator produces better results than a $15,000/month stack run by someone who does not understand the fundamentals. Buy the minimum viable stack for your current stage, get it running well, then upgrade. The biggest waste in B2B outbound is enterprise tools at startup scale.
What is the minimum viable outbound stack?
Three layers: data (Apollo free or LinkedIn Sales Nav), infrastructure (Google Workspace domains with Instantly or SmartLead), and sequencing (Instantly or SmartLead). Total cost under $200/month. This is enough to run 300-500 outreach sequences per month, which is plenty to validate whether cold outbound is a viable channel for your product. Add layers once you have proven the motion works.
Apollo or ZoomInfo -- which should I choose?
Apollo for almost every company under $10M in revenue. It has 270M+ contacts, solid email data, and a free tier that lets you validate the platform before paying. ZoomInfo has better enterprise account coverage, more direct dial data, and more intent signal integrations -- but it costs 5-10x more and the sales process is painful. Use ZoomInfo when you specifically need enterprise-level contact data or direct dial numbers at scale, and Apollo's data quality is consistently producing misses.
When should I add Clay to my stack?
When you have a defined ICP and you are running sequences consistently but want to enrich contacts with signals that make personalization possible beyond first name and company name. Clay makes sense when you can describe your ICP precisely enough that automation can identify them (not just 'SaaS companies' but 'SaaS companies, 50-500 employees, using Salesforce, actively hiring SDRs'). If your ICP is still being defined, buy Clay after you have had 20+ discovery calls and can describe your best customer in specific criteria.
Is Salesforce worth it for a startup?
Almost never below 50 employees. Salesforce is powerful but it is a significant implementation and ongoing admin tax. HubSpot handles the CRM requirements of most companies until they reach complex territory management, custom data model requirements, or enterprise deal desk workflows. Switch to Salesforce when a specific workflow requirement cannot be met by HubSpot -- not because you 'should' use enterprise software.
What do I cut from the stack if budget is tight?
Cut in this order: calling tools first (nicest to have, least essential), signals and intent second (high ROI but not day-one essential), advanced CRM features third. Never cut email infrastructure quality -- burning domains is the most expensive mistake in outbound and it is irreversible. Never cut email verification (BounceBan or equivalent) -- a single batch of bad emails can damage your sending reputation for months.
How long does it take to build and run a working outbound stack?
Starter stack: 1-2 days to set up, 2-3 weeks for domain warmup, first sends at week 3-4. Growth stack with Clay: 3-6 weeks to build enrichment tables and pipelines properly, then running campaigns by week 6-8. Scale stack: 2-3 months for full implementation including Salesforce integration, intent data setup, and team onboarding. The infrastructure warmup window is fixed regardless of tier -- no domain should send cold email before 14 days of warmup minimum.
We implement these systems end-to-end. First sends within 14 days.