Bart's Exchange
From PinataIsland.info, the Viva Piñata wiki
One of the village shops. By purchasing tinker tickets here, you can have Bart transform items for you. Later on in the game, Bart can also perform upgrades on your tools whenever you have reached a high enough level. Tickets come in different values -- Bronze, Silver, and Gold. The higher the value purchased (gold being the best), the better chance of a tinker being successful.