Diver Dan beat me to it !!
you'll also need fins. force fins are excellent but also around $125.00
i had an old caddis float tube that had a strap between your legs holding up the front of the seating area. if they still have this, look for one with some type of padding on it, so it won't rub the crotch of your waders. storage? fly rod holder? backrest? ease of inflating? weight? maybe a small anchor for brezzy days? be safe and have a blast.