Instead of waiting 30 days, 60 days, or more to collect payment from your customers, you can get paid in 2 or 3 days by asking them to pay you with a credit card instead of having you bill them. You'll have to pay a percentage of each sale to the credit card company, but that expense may be negligible when you consider the time and money you'll save by not having to send out monthly statements.
This is a win-win arrangement. The customer can still string out payments, but you're not on the end of the string. An added bonus: speeding up cash flow can help you speed up payments to your creditors, which may lower or eliminate interest payments you make on your payables.
If you don't think you'll have enough sales to warrant getting a merchant account, consider accepting PayPal. Many consumer and smaller businesses are familiar with and use PayPal for paying for merchandise or paying bills.
How to Get a Merchant Account for Accepting Credit Cards