Guests payan agreed donation - often in advance to cover "no shows" - providing the artists with a guaranteed income, often more generous than their share from a larger commercial event.
One of these is the way in which auction houses use third-party guarantees, where an outside individual or company agrees in advance to pay a set amount for a work sold at auction, in return for a cut of proceeds if the consignment sells for more than that.
Budget experts suggest doing a breakdown of where you spend every dime, but the simplest budget method by far is to remove a significant percentage of your pay in advance (double digits, at least) and deposit it into an account you cannot easily access.