http://www.kongregate.com/games/zinkinteractive/znpixelvania

This one is 4b*1 for coins, however it seems to crash if you change them and buy immediately after, whether you go up or down, if you go into a game after changing the value sometimes it sticks, sometimes it doesn't. If you go too high with the coins (like 999999999999) it will make it into a high score!

It seems touchy because if you enter the wrong number it will also crash firefox, not just the game.