Here is one of the cheapest CPU cooler for 1155, it's CLP0550 from Thermaltake, this cheap cooler also supported all Intel 1155 and 1156 socket that up to 95W TDP. Lot of features from Thermaltake CLP0550, one of them is easy to instal with Push pin design feature, silent operation and yes it's cheaper than another 1155 / 1156 CPU cooler on the market. The prices of this cooler around $19.99 (September 2011).
If you want to change your stock cooler for your Intel i7, Intel i5, even i3 that uses Intel 1155 or 1156 socket, Thermaltake CLP0550 is one of the best CPU cooler 1155 for money so far.. here is more info about this cooler