I have bought a few things from Walmart. You have to watch though if you order online, some things run small. I bought a nice mInnie shirt for my daughter in store for Disney and accidentally put in the dryer after washing, it definitely shrunk.
I bought a Disney Shirt from Walmart and while we were at the parks for 3 full days, my mom and I must have counted at least 20 people in that same shirt. It became a game to find people wearing the shirt.
I recently bought a Minnie nightshirt. Washed and dried it and it really shrunk a lot. It was ridiculous how much it shrunk. So, you may want to purchase larger sizes if the are all cotton.