I have been getting mine, 30x30, at Atwoods. This is a farm and ranch store in our area of Texas ansd Oklahoma. I know a friend , or maybe I should say second hand relative, that buys it by the bolt. I haven't been able to track down her Phone number but will post the info here when I get it. The ones I buy at Atwoods are 1.99 each. Sometimes I can pick them up foe .99 when on sale. The bin is getting low and I fear they may not stock them again. I do pick through them to get square ones as some have wonky corners.