Profitable and still running out of money? That is cash flow, and it has killed more Amazon businesses than bad products.
What is cash flow? It is not your margin in a spreadsheet. It is the timing of money out vs. money in.
On Amazon, money goes out early for inventory, freight, duties, ads, and fees. It comes back later through disbursements. When outflows arrive first and are bigger, the tank runs dry.
Why does it hurt sellers?
Front-loaded costs: deposit, production, freight, duties, prep.
Slow payback: sales today, cash later.
Inventory drag: slow sell-through, returns, storage surcharges.
Scaling tax: more SKUs, more working capital.
Ads first, cash later: PPC spends daily, disbursements arrive biweekly.
The 3 timing numbers that matter
DIO – Days inventory sits before sale.
DSO – Days from sale to payout.
DPO – Days you can delay supplier payments.
Cash Conversion Cycle = DIO + DSO − DPO.
Shorter is safer, but negative is the dream.
Here is a quick example:
You are selling a digital kitchen scale for $25.
Landed cost: $10
Referral fee (15% for Home & Kitchen): $3.75
FBA fulfillment fee (Small Standard, 8–12 oz): $3.72
Other minor fees: $0.25
Amazon fees add up to about $7.72. That leaves a $7.28 margin after fees, before the $10 product cost.
Now you place a 3,000-unit order on 30/70 terms.
At 50 units per day, you bring back about $365/day net after fees and ads.
By the first payout, you sold ~700 units → about $5,100 returned, but you already paid $30,000 before selling a single unit.
The product is profitable. The timing keeps you cash negative for weeks.
That is why sellers who look profitable on paper often collapse in real life.
