Some of my marbled plastic beach balls have held up through three + years of Gilroy temps (20's in the winter and 100's in the summer), which I think can beat up your Florida sun, Lin! (LOL!) Yes, they sometimes go flat, but I can pump 'em up with a bicycle pump. I usually find these in a big mesh bin in Tar-jay or a similar store.
I also have bowling balls and love them, but they're all the same size and I like having different-sized spheres in my garden!