I go through yoga/pilates mats like crazy at my studio. I let clients take them, I leave them at sessions, plus I bleach them so they begin to peel/crumble and i then toss them. I buy my yoga mats at http://www.yogaaccessories.com/yoga-accessories-1-4-inch-extra-thick-deluxe-yoga-mat.html
They have tons of color selections and a variety of sizes. The link is to the specific mat I choose. They are nice and cushy and I choose black. yes, shocking to those of you that know me--I usually choose black for most things! I also keep straps handy and about to purchase some blocks too. This site is great and has lots of selection.