If you're looking for a more grown up piggy bank, the red cup jar is the best choice.
This giant cup is perfect for students in college to save up their dimes and quarters to buy their next beer case. The iconic red cup will tie in with all a student's beer collectibles. While the piggy bank is easy enough to make, you'd have to think about whether you'd want to waste a cup that could be used for your next beer pong tournament to just hold your coins -- the best idea would just to get this from a store.
The red cup jar is the perfect student accessory for hosting keg parties as well; just be sure no one accidentally drinks for this and gets a mouth full of money.