What rear disk brake kit for rear of 91 fullsize Chev

I have a 1991 C1500 that i want to put rear disk brakes on but not sure what kit to use. One thing i do not want to do is spent a mitt full of cash.

speedway motors has nice cheap kits
http://www.speedwaymotors.com/10-and-12-Bolt-GM-Bolt-On-Rear-Disc-Brake-Kits,14015.html