$400, and it doesn't leak, it turns on and off and it has heat? Giddy up! I wouldn't put it inside, it's bound to leak in the very near future. I wouldn't spend much money fixing it up either.
New tubs run around 5-10k and up, so if your not really in the market for a new tub, but wouldn't mind sitting in hot water and having a drink....go for it.
Make sure it's safe. I'd look for a UL or ETL rating on it, and make sure old neighbour hasn't taken it upon himself to rewire the tub or something like that.