Unfortunately, if you follow most accepted methods of
bankroll management, Full Tilt doesn't really offer cash games for those with $100 bankrolls. Unless you can reload if you lose your $100, in which case your effective bankroll is higher than $100.
But 5/10c NL is as low as they go, which means you've only got 10 full buy-ins with a $100 roll. So SnGs or MTTs are your only real option there - if it's any consolation, their low-level SnGs are pretty easy to beat.
Otherwise it's like Van says, you're looking for 2/5c NL (or below, I guess, if you want to play it safe or go on a downswing) on Titan.