MONEY!

cults3d

Using money is a key math skill for life. It's also a great way to learn about addition, subtraction, and fractions. This thing has five coins in denominations 1,5,10,10,25, and 50 so you can print any combination you want. Well, maybe they're not completely free. The 1 cent coin uses about 0.3 grams of filament which, at $30 per kg of spool, equals about 1 cent of plastic. Quarters use about 0.5 grams of filament for a cost of about 1.5 cents per coin.