I recently bought a Q Industries Master Flow Tsunami MF 1050 on Ebay for ~$35 + Shipping, which to Canada after everything cost me about $75.
It comes with a 16 foot coil hose, enough to easily reach all 4 tires. The screw on chuck is easy to use.
Has a very convenient case.
My only complaint, the gauge is not accurate.
Easily hooks up to the battery and sits on the ground.
It took a hair over 3 minutes to inflate the Stock 32" Rubi tire from 20 PSI to 40 PSI... yes I had to deflate it.
Construction of the unit is very solid, it gets hot with use, but I could easily pull the chuck off after the single tire test. I suspect, after 4 tires it will be very hot. You would need to wear a glove to pull the chuck off the unit.
The unit is meant to be run no more than 30 minutes at a time, but because of the speed, I would think you will rarely if ever need more than 30 minutes to inflate 4 tires.
All in all, for the price, this is an excellent unit.
It can be found on Ebay (make sure you get the Tsunami, not the cheaper version), summit racing, and several other places. In the past, it has sold under the Superflow name as well.