So I've been experimenting with the battle-zone stuff. It seems being sneaky and doing bonus cards are a terrible way to farm for cash. If you can get a sneak attack thats great. But you wast alot of time sneaking and trying to do what the bonus says.

I find just running in and start taking down every trainer you can find as fast as possible is better for cash. Came out with 28 wins and 50k cash in pocket.

I think bonus cards are better if you are looking to level your rank faster. Im not sure if bonus cards give you more exp though, so thats still out.