I buy the "Oops" paint at Lowes to use when I redo various pieces of furniture. I bought an old baby changing table for $5.00. I mixed a couple of the small paint containers and got a lovely light lilac.
This is a page about buying mistake ("oops") paint. One way to save money on paint, if you are flexible on the color, it to buy the paint mistakes at your local home improvement store. Those mixing errors can be good for your pocketbook.