I can't find them in Walmarts in my area, however, the local grocery store carries them.
I have told all my friends about color catchers, even the non quilting ones. It's always good to know how to keep your kids' Christmas clothes from being ruined.
I read a tip somewhere before I finished my first quilt about how important the care for a quilt is. Whenever I gift a quilt, I always include care instructions and a couple color catchers. If I ever have to send a quilt in the mail, in big black marker I write on the box not to use a box cutter, razor blade, or scissors to cut the box open.