29 Oct 2009
Whilst playing through Scenario Campaign Mode, defeating enemies and/or breaking crates will cause money to drop in the form of bags of gold or treasure chests. Pick them up and it will contribute towards this achievement. Usually the boss of every level will drop quite a lot of gold so this might be helpful. You will more than likely get this through regular playing but if you want it fast, keep playing through any levels that give you a lot of gold and that's easy and it will all add up.