Best car to learn a manual and keep?

I describe myself as a baby enthusiast that can't quite get into the car hobby because money. Being not 24+ also bumps up the insurance quite a bit. Even more if I get a sports car.

With $15k, what should I get to learn manual? I learned to drive on automatic. Doesn't have to be too practical since I have access to my parent's car for that. Also I live in florida, we do have a decent amount of stop n go traffic.