They really aren't. I have several sets myself. Some from the local yards, where they're plenty cheap.
Even on Ebay they aren't horrible. $102 for a loaded set of brakes. I've bought from this seller before too, good guy. And if you miss this auction, he lists them pretty frequently. I bought one of my sets there before I found some in the yards.
http://www.ebay.com/itm/11-2-5-PLATES-LOADED-MOPAR-DODGE-PLYMOUTH-8-3-4-DRUM-BRAKES-8-75-NEW-YORKER-/281531523385?pt=Motors_Car_Truck_Parts_Accessories&hash=item418c962139&vxp=mtr
