Picked up one of these at Costco for $80.00US. It includes a pretty good (150psi) air compressor, jumper cables, two 12v power outlets, a 400w, inverter, flashlight, onboard recharge, and a battery meter and air guage.
It's about the size of a small duffel bag, and looks pretty well-designed. The air compressor got one of the motorhome tires filled really fast.
Boondock traveler, Frugal, but never "cheap".