IOGear GKM561R 2.4GHz Multimedia Keyboard with Laser Trackball for $28.99 shipped after this $7 rebate.  Here is a screenshot for your reference.  This wireless 2.4GHz keyboard features built-in laser trackball, mouse buttons with built-in scroll wheel, 19 hotkeys for multimedia functions, slip Resistant design, and more.  Most places have this Wireless Multimedia Keyboard for about $39.