I think their should be a upgrade slot for scavenger that when you kill and enemy when you have 1 point in scavenger that you have an 50% chance to get double the EXP and coins + this to let the makers see and put this in the update!
I think the gun prices are ok but 1 kill 1 coin... they should do it like 1 kill 2-3 coins and a flag 6-7(Not 5 coins for a kill cause then combos are MORE OP)