I bought one of these to take with me to the beach - so I can refill after lowering tire pressure for (legal) beach 4-wheeling.:
http://www.cpocampbellhausfeld.com/a...p209500rb.html
Not the most powerful. It takes a few minutes per tire, but was cheap, is light, and works.
I bought mine new, non-factory reconditioned, from a Lowe's Home Improvement Warehouse, which may or may not operate in your state.