A Game Ticket is an amassable item that is collected and redeemable in both games. It is similar to a Lucky Medal in that it can be collected in large quantities and then redeemed all at once at a certain location. Game Tickets are often handed to the party for free by any vendor whenever the party makes a particularly expensive purchase from that vendor. They can be used in the Lucky Wheels minigame located in Tolbi in Golden Sun and in Contigo in Golden Sun: The Lost Age, and the prizes include the main shirts, boots, and rings that can be found in either game. They can be refused when offered by the vendor, sold for 37 coins, and bought back as an Artifact for 50 coins.
One way to farm Game Tickets is to buy 30 Nuts from an Items vendor then sell them back. With a buy value of 6,000 and a sell value of 4,500, this results in a loss of 1,500 gold per purchase/sell. Repeating this, starting with 20,000 gold, will net about 8 Game Tickets in 5 minutes. Note that a Ticket is awarded every 3 of 4 times you buy a stack of Nuts, resulting in an average cost of 2,000 gold per Ticket.
Another way to farm tickets is to buy and sell a cheap artifact repeatedly, like the Magic Rod. Buying the Rod costs 380 and selling it returns 285, costing 95 coins per ticket. Buying an artifact seems to generate a ticket every time.