This achievement may seem daunting, especially when you are at a lower level and scanning keepers for 30 credits, but it is actually one of the easiest. What you have to understand is that you earn more money per kill/mission/scan as your level increases. And the increase in earnings is ridiculous. Killing a regular Geth trooper at level 50 nets you 10 000 credits. You get even more for completing missions and killing stronger enemies. Therefore, if you want to spend money, go nuts. It doesn't make sense to resist buying that 2000 credit gun at level 5 when 2000 credits becomes less than a penny later on. At level 50, having completed most assignments, I have 10 000 000, and I don't know how I could spend it all if I wanted to. Don't bother with the infinite money glitch - far easier to earn the money naturally.