I have long wanted an interesting piggy bank for myself, and as I am a fan of Gravity Falls I could not pass by this model of Waddles ( https://cults3d.com/en/3d-model/art/waddles-easy-print-no-support ). Having conjured a little, I turned it into a piggy bank, adding only a twisting one from the bottom plug. I really liked the model itself, now I'm starting to save up for a new 3D printer ...
When printing in a slicer, I recommend setting 4 layers of the bottom and cover of the model.

video: https://youtu.be/hC7vzIuTqz4

Check out my other models:
https://cults3d.com/en/users/Hom_3D_lab/creations