Affiliate MarketingvsCustomer Acquisition Cost (CAC)

Affiliate marketing is a purely performance-based acquisition channel where a business pays external partners (affiliates) a commission for generating specific, measurable actions (usually sales or leads). It fundamentally shifts the risk of marketing spend away from the brand and onto the partner, functioning as a variable cost rather than fixed advertising overhead.

CAC is the total cost of convincing a potential customer to buy your product. This includes all marketing spend, sales team salaries, tools, and overhead directly tied to acquiring new customers. The formula: CAC = Total Sales & Marketing Spend ÷ New Customers Acquired. A company spending $50K/month on marketing and sales and acquiring 100 customers has a $500 CAC. CAC varies dramatically by channel — paid ads might be $300 CAC while organic content is $30. VCs obsess over CAC because it determines unit economics: if CAC exceeds LTV, every customer you acquire destroys value.

The biggest trap is paying out commissions for 'coupon poaching.' If a user is already on your checkout page and opens a new tab to search for 'Promo Codes,' an affiliate ranking for that search term will capture the cookie and take a commission for a sale you had already organically won.

The most dangerous mistake is calculating 'blended CAC' by averaging all channels together. This hides the fact that your Google Ads channel might have a $200 CAC while organic has a $5 CAC. Blended CAC at $100 looks fine — but if you scale by doubling ad spend, CAC doesn't stay at $100; it approaches $200 because you're scaling the expensive channel. Always track CAC per channel. The second trap: excluding sales salaries from CAC. If you have 4 sales reps at $10K/month each and they close 40 deals/month, that's $1,000 in 'hidden' CAC per customer on top of marketing spend.

Implement strict terms and conditions for your affiliate network. Ban 'brand bidding' (where affiliates buy paid ads against your company name) and implement a multi-touch attribution model or at least a strict 'first-click' vs 'last-click' policy depending on whether you want affiliates to drive new discovery or close existing intent.

Calculate CAC by channel: Paid CAC, Organic CAC, Referral CAC, Outbound CAC. For each: total spend on that channel ÷ customers from that channel. Kill channels where CAC > LTV/3 (not LTV/1 — you need margin for overhead). Track CAC trend monthly — increasing CAC often means market saturation or competitive pressure and requires immediate investigation.