If your traditional mouse has been taking up too much space on your desktop, Logitech's new M575 not only frees up your desk but also keeps your hand and forearm comfortable with its ergonomic design. The ergonomic shape maintains a comfortable space for your hand and since the trackball is fixed, you don't need to take up any more desk space. Comptiable with Macs, iPads, and PCs, the M575 also can stay charged for up to two years with a single AA battery when used with the included wireless receiver. 

$49, logitech.com