Buy.com offers the IOGEAR Multimedia Wireless Keyboard, model no. GKM681R, for $29.99. This $12 mail-in rebate cuts it to $17.99. With free shipping, that's $7 under our May mention and the lowest total price we could find by $14. This 2.4GHz keyboard features an optical trackball, scroll wheel, 16 multimedia hotkeys, and more. It requires two AA batteries (not included).

Note that while this keyboard is Mac compatible, the multimedia hot keys are not supported.