Collecting payment before delivering a product or service — deposits, pre-orders, retainers paid in advance — is one of the most underused ways bootstrapped businesses fund growth without debt or investors.

Where this works well

Custom or made-to-order products, where a deposit is standard practice anyway
Service retainers, where clients pay at the start of a billing period rather than after work is delivered
Pre-selling a new product or service to gauge demand and fund initial production simultaneously

The discipline it requires

Pre-payment funds growth, but it also creates an obligation to deliver — track pre-paid commitments carefully so the cash isn’t mistaken for pure profit before the corresponding work is actually done.