me and a very deer lady friend stopped at a garage sale and got her some old windows to do her art work on, and I also saw a guy use old cabinet doors
old skate board decks, anything wooden? shingles (siding) cardboard, paperbag...go to the Goodwill?
There are other materials than canvas. The real cost is the fr<x>ame. I am serious, here. Have you considered dumpster diving for framing materials? There is always somebody doing some sort of renovation to one house or building or another in any town of any size. If you live in the USA, look for the temporary blue dumpsters. Once you have the (I suppose) wood, you can buy fasteners at the hardware store for cheap to make the fr<x>ames. Canvas or other fabric cab be found at any fabric store. Remnants are cheap as hell and probably can easily cover a smaller sized fr<x>ames like the ones for hand prints.<br />
Never give up. There is a way for you to get what you need without resorting to debt or debauchery. Good luck and have fun.
anything cardboard, wood, card, paper, ect.<br />
As long as it's planned and prepped anything will do
bed sheets stretched over something like cardboard or a fr<x>ame if you can.
burlap stretched tightly maybe
Posterboard, or construction paper.
use your toilet paper roll for your ****