How it works
This is the number that actually matters: what you keep. It takes your break-even CPA (price minus cost minus fees) and subtracts what you actually pay to acquire a customer. Positive means profit, negative means you are funding your own funeral, one order at a time.
Most people scale on revenue and go broke. Profit per order and net margin are what compound. If the number is red, you do not have a product problem or an ad problem yet, you have a math problem, and the fix is almost always price or creative.
A negative result does not always mean kill the product. Sometimes it means your CPA is too high because the creative is weak or the account is wrong. See the multi-account playbook before you write off a product.