SK-7 is $20 at svc.com and cools almost as well as an SLK-800, given the same fan. It has full copper construction and takes 80mm fans (or 60 x 25's too). If you get one, take note: it can slide back and forth on its clip a bit. When you hook the non-screwdriver end of the clip to the CPU socket, pull the heatsink to that end so it's as far away from the solid-plastic end of the CPU socket as it can go. Otherwise it can get jacked up on the solid-plastic end of the CPU socket and then it won't make flat contact with your CPU core.
(oh, and the YS Tech 80mm adjustable fan is a good pick to go with that, you can dial up the noise/cooling level you like)