I just bought a yoga ball and bounced away on that for baby 1. I didn’t use it till it was over 32 weeks tho but that’s personal preference.
I think they are very similar, I got this one last time round and using it again already ☺️ https://amzn.eu/d/hWBlO9X
Yhh you can use a normal gym ball but I’d advice to use it for exercise only I wouldn’t bounce on it yet or swing your hips on it . X