This is a very very easy way to get 400,000 or 500,000 or even yet free items.
1.Go to Serrano Campaign you can ether do Online or 1 player but
NOTE* that online you get way more items and money easyer.
2.Go to stage 1 or 10 it depends how good you are and life you got....
NOTE* That on stage 10 you'll get the most money than all the stages, with the helicopter or if you don't know what is stage 10 its the longest stage on the game when you have to fight 2 or 3 bosses..
3. Make sure to beat the whole stage first than save it or you'll loose all your money.
*Than your done*
Now if you want a lot of money go to online Campaign.