You could have it so that you get 2 sets of 255. 1 set is the wallet and the other is the Bank Bags (once you get to 255 in wallet, it adds 1 into this and it would reset the wallet). But I did't mess around with that. Also if you want to have it so that it keeps going, make it do it one coin at a time and have it read the random number and do it that many times.
e.g. you have 250 gold in wallet and 0 bank bags. You get 15 gold from an enemy. It counts up and now you get 10 gold in wallet and 1 bank bag. You reset back to the 250 gold, 0 bags state. You kill the same enemy but this time, you get 5 gold. You now have 0 gold and 1 bag.
But I haven't made a game with a money system yet so... i don't now about this.