The Piggy Bank is a way to collect Gold Bars and buy them at a discount over the bundles available in the store. You can spend Gold Bars to buy extra lives or to keep playing a level after you’ve run out of moves.
Winning levels adds more Gold Bars to the Piggy Bank. The more stars you earn, the more Gold Bars you’ll receive. If the Piggy Bank is already full, then the Gold Bars will bounce off.
When the Piggy Bank becomes available, you can choose either to unlock for the amount stated, or to keep playing and fill it with more Gold Bars. You’ll also be notified once the Piggy Bank is full.
After you’ve opened your Piggy Bank and received your Gold Bars, you’ll get a new Piggy Bank to fill.