During the many discussions on using paint as a glue to adhere the canvas to foam, many have mentioned ways to get low cost paint (mis-mixed paint, Habitat Re-store, just what is leftover in the basement). I found out today that our city household hazardous waste division has a "store" where usable items dropped off can be picked up by those that would have a use for them. The price is a whopping FREE!. The most common item in their inventory is paint. Some full gallons. They even take the partials they get and try to mix custom colors in 5 gallon buckets. So, check with your local hazardous waste center if you need some paint for your foamie. You might be able to get it for the ultimate thrifty price.
Bill