You can also play around w/ mixing different colors to get a shade you like, especially since so cheap.  Just make sure to use either latex or oil seperate.

Leftover paint is so fabs.  My friend does up his apartment bi-yearly in a sort of paint-sale-roulette.  Sometimes its a wonderful thing... and even when it's not, hey, it's cheap and fresh. 

In my area Habitat for Humanity runs a shop called ReStore.  They take donations from remodeling or overstock from the hardware stores and resell it to help fund their other projects.  The ReStore also takes buckets of paints.  So like alexrussell says if you don't care much for the color; it can be a good place to get paint cheap.