Tobi is one of the best F2P ninjas in the game, and they've already confirmed he's getting a nerf down the road to reduce his damage, remove his passive ability to dodge Ninjutsu special attacks, and remove his resurrection ability.
You're obviously not in a server with a bunch of cash-heavy players if you're running into Tobi and having an issue with him, and he's one of the only reasons free players like me are able to contend with cashers who have triple Kage lineups or highly refined Sage Naruto teams.
So not to sound like a *, but for the time being: Deal with it.