I'm trying to make a capsule machine similar to the trophies in Smash Bros: Melee where the more coins you pay, the better the chance you'll get a trophy that you don't already have.
So basically it'll be like:
And if you insert one coin, you have a low chance of getting Trophy 4, but the more you insert, the higher your chance of getting that trophy (or any you don't already have). I just don't know how to go about this or the maths involved. Any help would be appreciated.