There is a huge thread on this very subject. I can't remember which forum, but I think it is this one. I don't feel like looking it up, but you can. Basically, anywhere from one to two times the cost of the ARF. For a 30%, and a good job, the man probably spent at least 30 hours putting it together and setting it all up. Probably more like 50 hours if he set the radio and engine up for you--was it ready to fly? If so, then probably in the neighborhood of 300 to 500 dollars would be the going rate. Of course, we all have friends who will do things for their favorite cold beverage, so this is going to have to be a personal decision, ultimately.