It depends a lot on your location. I paid$300.for a 67 bronco 9" complete drum to drum I bought another 9" bronco last week for $200. I am a cheap-***,and these were the best deals I could find. The wide pickup rear ends are cheap,but kind of hard to use under anything but another truck.
Out here in socal a nine inch with posi and 32 spline axles can be anywhere from $1600 To $2500, depending on what type of brakes. That includes narrowing and brackets welded on. If it's a bunch cheaper elsewhere you guys are livin' good.
I paid $100 for one out of a 78' Pickup. Complete hub to hub. It was the right width for my channeled model a sedan.