Amazon offers Prime members the Black + Decker 1/4-Sheer Orbital Sander, model no. BDEQS300, for $21.43 with free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $7.39.) That's the lowest total price we could find by $11. It delivers up to 1,600 orbits per minute and features tri-layer filtration and a soft grip paddle switch.