Invoice financing lets you get paid for your outstanding invoices right away -- for a fee. The approval process is short and simple -- you just need invoices (of course), a history of more than three months in business, and at least $50,000 in annual revenue. Additionally, your credit score is sometimes a factor in availability and terms.

For businesses that already have solid cash flow, invoice financing may be a sensible choice.

It allows you to finance 50 to 90-plus percent of the invoice amount and then repay it when the client pays you.

There are some cons, though. Fees are higher than those of traditional financing. Also, the longer it takes a client to pay, the more you owe, so it's best to use it in cases where clients are reliable payers.