If you're painting a tiny space -- on a tiny budget -- you might want to check out this offer from Home Depot! Right now, all of their 237 mL size "tester" pots of Martha Stewart Living Paint are just $1, plus a 50¢ environmental fee. The cans are usually priced at $4.99. It will take several tester pots to paint even the smallest room (a forum poster was able to do his powder room with just four cans) but considering the standard cost of a gallon of paint, it's a nice deal.
The Martha Stewart Living Paint line is being discontinued, so stock will likely be limited. The tester pots come in twelve colours -- you can see samples of the colours on this page from HomeDepot.com.