I use fabric quarters a lot. Love them! Check out The Fabric Shop on Etsy. I shop there a lot. Love it. Here is a link for you:
Fabric Shoppe Great Prices on Modern Designer by fabricshoppe
They have it set up so you can look only at quarters if you want. Great customer service and fast shipping too. Lol. Listen to me I sound like I work there, but seriously I do enjoy that shop. Etsy has all sorts of great shops. Bigger variety too.