Abstract: A preexisting gaming machine is adapted or retrofitted to print valid tickets for a game player at low cost. The preexisting gaming machine includes a game microprocessor for controlling game operation (e.g., slot machine operation) and includes a cashout signal input. A game interface is fitted to the gaming machine and coupled to the game microprocessor for controlling ticket printing and redemption in conjunction with a central authority. A memory in the game interface stores a pre-loaded ticket validation number received from the central authority. In addition, a ticket printer is fitted into the gaming machine and coupled to the game interface for printing a ticket that includes game credit indicia and pre-loaded ticket validation indicia. The game interface controls printing in response to a cashout signal. After the ticket is printed, the game interface obtains a new pre-loaded validation number in preparation for the next ticket printing event.