Prisons are hugely profitable (see the video elsewhere of the Louisiana sheriff) and the prison industrial complex throws off so much cash that its lobbying effort is one of the largest in California (and is why we still have, for example, the three strikes law)
I said "yep" because I figured you were asking a general question; in the specific case Walmart's position is that they don't use prison labor (but plenty of web sites will tell you it's not true. Here's Huffpo: https://www.huffingtonpost.com/al-norman/walmart-prison-labo...).
At WalMart, yes. Also JC Penny, Victoria's Secret, K-Mart, and Starbucks have all used prison labor. There's also prison call centers, such as those used by American Airlines and Avis.
Are prisons really profitable though? Do they produce anything of real value from this free labor ?