From RWP Wiki
The Jiggy Bank is a large dome that sucks up Jiggies and adds them to the game's total. It features large golden numbers showing how many Jiggies are currently inside.
In the Games
Banjo-Kazooie: Nuts & Bolts
In Banjo-Kazooie: Nuts & Bolts, the Jiggy Bank is located in the center of the Town Square in Showdown Town. Once Jiggies have been collected from their respective Jig-o-Vends, they can be carried and will be sucked up by the bank, at which point they will be added to the game's totals.