Just got this from Home Depot. Tired of putting coins in machines and having to get the trailer into places. This worked great on my 50 lb trailer tires. Home Depot for $50 ! Recommended
http://www.homedepot.com/p/Husky-12-Volt-120-Volt-Home-and-Auto-Inflator-HD12120/204260884
http://www.homedepot.com/p/Husky-12-Volt-120-Volt-Home-and-Auto-Inflator-HD12120/204260884