CPU Cooler:Xigmatek GAIA SD1283 56.3 CFM CPU Cooler ($24.99 @ Newegg) Total: $24.99 (Prices include shipping, taxes, and discounts when available.) (Generated by PCPartPicker 2013-08-23 10:09 EDT-0400)
Take your pick. They all three named above will cool about as well and are attractively priced.
When you factor in running at comparable fan speeds, each will cool about the same at equal temperature deltas