Ends 8/15 at 7AM PT. Adorama has the Acer Predator Cestus 300 Wired RGB Customizable Gaming Mouse with Dual Omron Switches and Up to 5000 DPI (Black) on sale for $25 with free shipping.

If you're willing to risk it, eBay seller wgsolutionsinc (1108 / 100% positive feedback) has a couple left for $22 shipped.