what kind of turtle is this?

It's a river cooter for sure, river cooter's develop those bumps, mine is starting to develop those too. Cute Turtle

i would have to say its a florida redbelly, river cooters stripes arent that thick and have the c on the middle scute, where did you aquire the turtle?

looks like a yellow belly slider to me

I agree with Demonbloodmage ,I think its a river cooter.

Hello,
That looks a whole lot like a Florida Red-Belly (pseudemys nelsoni), I actually own one. The only other species I would imagine is a River Cooter. One thing is for sure, it is certainly a cooter. Hope that helps.
(They like greens, lots a veggies!!)

Reading the other comments I would also like to kindly refute "nevermind" in his assesment. I have a Yellow-Bellied Slider as well and that is not a slider. The shell pattern on top is that of a cooter.