Well, there are several hidden trophies so... who knows.
Discovered an exploit yesterday that gives you pretty much unlimited money. Yeah, it's cheap but I've beaten the game already and considering all the cheap deaths and bugs, I don't mind using it just to keep my weapons repaired and too buy enough detergent and scrap metal to make ammo... seriously, I can carry around 12 fricking swords or machetes or baseball bats but not a couple extra boxes of ammo?
Not sure what it would be on an X-box or PC but on PS3...
Hold L1 (like you're aiming to throw a weapon) and hold Triangle then tap R1. Your current equipped weapon will be thrown with a duplicate dropping at your feet. Pick them up, rinse, repeat and sell.
I tried this with the xbox but it dont work.