Then you've got a line of credit with your bank. Most businesses have that set up. Back when I was going to alot of machinery auctions, I usually had the bank issue a letter of credit for 50k or so, which guarantees payment to the seller for anything I bought up to that amount. Money would be wired into their account by the next morning.
You probably also have overdraft protection, which would cover any check you write to the payee, but would charge back to you any charges that the bank would levy. This keeps you from having to pay the $40 returned check fee to Wal-mart or the local feed store or whereever one writes a hot check to. But the bank will hit you pretty hard with their insufficient fund fees and every other fee they can think of.
It's always nice to be able to run a bad check through someone's account several times, forcing them to pay the bank fee each time, whenever you call them and let them know their check bounced and they lie to you and tell you they didnt realize it or it must have been a mistake or that they will come right down and make it good. Each time we run it through they get charged a insufficient fund charge. Costs me $2 bucks each time, but sometimes you get lucky and run it through right after a payday deposit and the check clears.
The fun part of running your own business, dealing with the low lifes who have no intention of ever paying you for the work you do. Employees never see that part of it, they just think we sit behind our desk while the Brinks trucks unload piles and piles of money at our feet!
