The lesson
Ecommerce looks simple from the outside — buy low, sell high, online — but the money is made or lost in the details of unit economics. Every sale has a selling price, a product cost, a shipping cost, transaction fees, and, crucially, a cost to acquire the customer (ads, mostly). What's left after all of that is your actual profit, and beginners routinely forget the acquisition cost and the fees, then wonder why revenue is high but the bank account is empty. The core equation to burn into your mind: profit per order = price minus product cost minus fulfillment minus fees minus ad cost. A store is a machine that must turn one dollar of ad spend into more than one dollar of profit, repeatedly. Everything in this arena serves that machine: finding products with enough margin, building a store that converts, and acquiring customers profitably. Master the economics first and you avoid the most common way stores fail — growing while losing money on every sale.
Key points
- Profit lives in unit economics, not revenue.
- Always include ad cost and fees in your math.
- A store must turn $1 of ad spend into >$1 profit.
Your exercise
Write the full profit-per-order breakdown for a product idea: price, product cost, shipping, fees, estimated ad cost.
Inside Cobra Arena you submit this exercise and get graded feedback on it — free with an account, no card needed. The rest of the arena comes with membership.
Do the exercise free