In addition to Rinky's suggestion, Home Depot also carries a small portable compressor that works off a 120V outlet. It's perfect for small jobs like airing up tires on cars, bikes or sports balls. Cost is about $100 and can even fit in smaller cars if you have an emergency.
![](http://www.homedepot.com/cmc_upload/HDUS/EN_US/asset/images/eplus/732422012582_4.jpg)
I know what a PITA it can be to drive all over creation only to find everyone's gas station air hose is broken.