How does it work?
Instead of filling the Piggy Bank and then buying it, you can choose whether to have a Piggy Bank or not. Just buy an empty one! Once you have purchased one. Work towards getting those tasty Gold Bars. It's your choice!
Fill up your empty and pre-purchased Piggy Bank by collecting stars when you beat a level. For each star you win, you'll also win one gold bar to add to the Piggy Bank. The more stars you get the more gold bars will be added to the Piggy Bank. Especially on those 'Hard' and 'Super Hard' levels!
Once you have filled the Piggy Bank (up to 30 Gold Bars) that you have previously bought, you will have the chance to break it and obtain all those shiny Gold Bars! You can buy the new Gold Bars as many times as you want.
Try updating your game to its latest version. If your game is already up to date, and you can't see this feature. Don't worry! Sometimes you might have access to it and your friends may not, or vice-versa. Keep in mind, you may have it when they don't too. You will be able to enjoy the new Piggy Bank eventually.