Which pet is better: a sugar glider, hermit crab, turtle, beta fish, gecko or frog?

I'm looking into getting another pet. I already have a 10+ year old cat, one large fishtank with 3 big fish, and another fishtank with 4 goldfish. I love animals and I really want one. Which one of these would be the best? I don't have too much money or too much space. But I really want another pet. If I do get one of these, where can I get them and how much are they? Pros and cons? Whatever you know about any of these animals, please let me know! Thanks in advance!