Any towable will beat up the rider... but I really hope you aren't going to put a 3 year old out on it. (unless they are excellent swimmers) Even a big towable, with an adult on it... if there is a problem, it could end badly.
OK... with that said... Sevylor had an outlet on eBay, and last year I bought 2 things from them. The larger of the 2 was a large, delta shaped two person inflatable with an inflatable windshield, and a nylon shell with a 4 point harness built into it. Even with 2 adults... it did not submerge.
Oh... and the best thing was... it only cost me $25 shipped!!!
The other thing was a large inflatable play house for my kid. ($13 shipped, new retail was $70)
My personal opinion is... get one cheap if you can... because it won't get used much. All of last year... mine only hit the water twice.