If you don't care about what difficulty for SA Hanzo, easy mode is also pretty cake to run as a f2p player (I'm one myself). I use this guide (http://forum.naruto.oasgames.com/en/forum.php?mod=viewthread&tid=3571).
As for a good Earth main line up, the one I ran that was REALLY good was GNW Kankuro/Guy/Jigo but since you don't have any pains, perhaps I'd suggest running someone like Tsunade instead?
What ninjas/summons do you have? I could probably find another substitute lineup for you.