For those looking for a gaming mouse that's Linux friendly and not too expensive, the ROCCAT LUA is a nice option.
The ROCCAT LUA is a tri-button gaming mouse that features an ambidextrous v-shape design, no-sweat side grips, and soft-touch surface. The LUA also allows for the sensor DPI to be easily changed via a physical button on the top of the mouse with its Pro Optic R2 sensor supporting a DPI range from 250 to 2,000.
As with ROCCAT's other products, they are Linux-friendly. Linux support isn't advertised on the product packaging, but going back years ROCCAT has helped support Linux. As explained on the ROCCAT site, "So, you want to own with ROCCAT gear but you use Linux? No problem! These aren’t official ROCCAT drivers; rather, they’re coded by enthusiastic programmers. ROCCAT is keen to support him wherever we can, and we are delighted to have such an active community." The ROCCAT Linux project page is hosted on SourceForge.