The Paid Traffic Operator
Unit Economics 101 for Affiliate Media Buyers
3 min read
Every paid course throws a wall of acronyms at you: EPC, CPC, CPA, CPM, AOV, LTV, ROAS, MER. You don't need to memorize them. You need to internalize one sentence: revenue per click must beat cost per click, with enough margin to survive variance. Everything else is bookkeeping.
The five numbers (and how they connect)
- EPC (Earnings Per Click): what the affiliate program actually pays you per click you send. Get this from the network — don't trust the offer page's "up to" number, which is a top-decile figure.
- CPC (Cost Per Click): what the ad platform charges you per click. Reported in every campaign dashboard.
- CR (Conversion Rate): what percentage of clicks turn into commissions. Multiply by commission to derive EPC if the network doesn't show it.
- CPA (Cost Per Acquisition): CPC ÷ CR. The amount you pay for one paying customer.
- ROAS (Return on Ad Spend): revenue ÷ ad spend. A 1.0 ROAS means you broke exactly even on revenue — before any costs.
The break-even math (do this once, then again per offer)
Suppose the offer pays $40 per sale and converts at 2% of clicks sent. Your EPC is $0.80 ($40 × 0.02). That's the ceiling — pay anything close to that per click and you make zero. To leave room for variance, fees, and the inevitable bad days, your real target CPC should be roughly half: $0.40 CPC. Anything above $0.60 should be on a short leash. Anything above $0.80 must be killed.
The kill rule (write it down before you launch)
The single behavioral fix that improves affiliate ROAS the most: decide your kill threshold before you launch the campaign and write it on paper. Once a campaign is live and you're emotionally invested, every number looks like "almost there." Pre-commitment is the only defense against hope-spending.
A workable default kill rule:
- If CPC > 2× target after 100 clicks → pause and analyze the creative.
- If CPA > 1.5× break-even after spending 2× your CPA target → pause for 24 hours.
- If ROAS < 0.7 after 5 conversions → kill outright.
Scale rules (the other half nobody writes down)
Most affiliates have kill rules and no scale rules — so winners get killed by random budget changes and losers get propped up by hope. A working scale rule:
- If a campaign is at >1.4 ROAS for 3 consecutive days with at least 10 conversions per day, increase budget by 20%. No more, no less.
- Wait 48 hours before increasing again. Algorithms hate sudden budget jumps and will reset learning.
The hidden number: contribution margin
ROAS is a vanity metric until you subtract every cost. Real contribution margin accounts for: affiliate network fees, landing-page hosting, tracking tools, refunds, charge-backs, and the time it takes you to make a creative. A 1.4 ROAS that looks great can be a money-losing campaign once you bake in the rest. Run a real contribution margin calculation monthly. It humbles your "winners" and helps you find the real ones.
The one rule above all
If you cannot describe, in one sentence, why a campaign is profitable today, you cannot scale it. Numbers without narrative collapse the moment something changes. Always know why the math works — which audience, which hook, which offer detail — before you press the scale button.
How to Get Started Now
- Look up your offer's real EPC (or compute it as commission × conversion rate) and write it at the top of your campaign tracker.
- Calculate your break-even CPC as 50% of EPC, and write that number on the launch sheet for the campaign.
- Write your kill rule and your scale rule on the same sheet, in advance, with dollar thresholds — not adjectives.
- Start with a $10/day budget, let the campaign run a full 72 hours before you touch it, then apply your written rules without negotiation.
- Run a monthly contribution-margin pass on every active campaign, subtracting all real costs, and reallocate budget toward the campaigns that survive that test.