SF Gate has a useful article that digs into the ins and outs of bootstrapping.

Bootstrapping is founded on two simple techniques. The first is time-shifting your payables into the future. You don’t have the cash today, so you say to people, “If you give me this resource today, I will pay you in the future.”

If you can do this on some kind of per-customer or per-transaction basis that you can document, people feel relatively confident — so (they know that) in every future transaction you do, they will get a piece of that transaction.

The second technique is barter. If you are in a business, you’ve got something that other people want. You don’t have cash, but you have a service, or software or a product.

Via Anthony Cerminaro.