The vending unit at the printer will not give change unless you print something. It used to, but it doesn't anymore. There is a sign on the top stating this.

If a patron puts a dollar in the vending unit, give them change from the cashbox at the computer lab signup desk. Next, log in to a PC and print one page. The printer will give you $.90 change. Put the change in the cash box and notify Cheryl Cornell.