its a good price for that unit, especially if they've maintained it well. don't spend too much on the inspection. not much they will find that you couldn't by operating all the levers and pumps, verifying it is heating, and checking for signs of leaking. if you can get them to flush it before they drain it. otherwise you will have to fill it at home, then flush it and refill it to start out right. try to get them to throw in a set of filters if they haven't replaced them. you'll be on the hook for $300+ in another year or so if they haven't.