From Toontown Rewritten Wiki

Tickets are a form of currency that is earned by racing and can be used to purchase a new type of kart or accessories for a kart at Goofy's Kart Shop. A Toon can obtain tickets by either qualifying in practice races, or by participating in battle or Grand Prix races. If a Toon competes in battle or Grand Prix races, they have to pay a certain number of tickets to compete but would always receive the exact number or more when finished, assuming they qualify.