Hardware Sales Inc via eBay offers the Makita 18-volt Cordless 1/2" Hammer Drill Driver, model no. LXPH01Z, for $39.99 with free shipping. That's the best price we could find by $21 and the lowest total price we've seen. This 4-lb. drill features 480 inch-pounds of torque, a belt clip, built-in LED light, 2-speed gear box, and more.

Of note, it requires an 18-volt lithium ion battery (not included). The product page states this may be a factory-second or new item with defects; however, it includes a factory warranty.