Makita XWT04Z 18-Volt LXT Lithium-Ion 1/2-Inch High Torque Impact Wrench at Amazon.
After the automatically applied promotion, it ends up $124.00 shipped. Tax for some.
This is part of the ongoing $25 off $100 Makita promotion going on at various tool sellers including Amazon. It's currently way below anyone else's price that I could find. I have 2 of these and they are great. Plenty of torque and have yet to find a lug it won't take off.
If you already have the Makita LXT system, this is a no brainer add-on in my opinion. Add one of these lug nut impact socket sets [amazon.com]
and you've got a powerful, portable alternative to an X-wrench, or worse, the stock tire iron. This has really made my life a lot easier including the occasional emergency tire change on the side of the road.