http://en.wikipedia.org/wiki/Compressed_natural_gas
There's a guy who took out a loan on a P2P lending site I visit who has 2 of these cars in Utah. Prices are less than 70 cents per gallon and I can't remember how far he could drive on a fill up, but it was WAY cheap. With the CNG sticker on his cars he also gets to drive in the HOV lane when he's alone
