From http://corporate.walmart.com/newsroom/company-facts (straight from the mouth, as it were) and ignoring shareholders for a moment, WalMart employs 2.3 million people. They also reported $10.4 (American) billion in profits. That works out to $376.81 per worker per month.

So it seems possible to give each worker an extra $100/month. But now you have to sell this to the shareholders, which may include institutional investors managing retirement accounts. Good luck figuring out that mess.