$7 Costumes at Walmart!! This post may contain affiliate links. Please see the full disclosure policy here. Posted on October 3, 2009 Written by Mary Leave a Comment WOW $7 Halloween Costumes at Walmart, starting TOMORROW(10/4)! (I suggest going early for the best selection). Check out the scanned ad GO HERE (thanks, SD) Thanks for the heads up, Mojosavings!