I love water aerobics! I bought the weights but looked at the belt and thought no way. First off don't believe the "one size fits all" stuff unless you are pretty thin. I tried it and it was way too short for me. BUT besides that, I figured why on earth pay $30 for a few pieces of foam tied together. I am going to go buy a couple of noodles, cut them in small pieces and tie two rows of them together and get the same thing.
Another great water "tool" I use is a plain ole frisbee. Standing in chest deep water just leap up really high and toss it as high as you can. Then jump up as high as you can to catch it... or lunge every direction as it comes down, to go after it... falling is not a problem. This really gets the muscles moving!