Grays of Westminster are selling one without lens for £149 with a 12 month guarantee, and the kit for £199. Considering that they have to make a profit my guess is your is mates worth a lot less than £250. The kit lens that came with it is okay and the D50 is an excellent camera but it isn't worth £250.
The D50 does have built in auto-focus motor so you don't need to but lenses with this built in. It was the best entry-level camera off it's time and is still an excellent camera.