Walmart has two samples listed currently: Airborne and BB Cream by Maybelline. Here is the link: http://instoresnow.walmart.com/In-Stores-Now-Free-Samples.aspx?&_prevTerm=free+samples&redirect_query=free+samples&search_redirect=true.
P.S. Target also has one of their makeup bag samples, but there are problems with the page. I’d recommend waiting, or skipping this one. I was on the page for half an hour unable to get the sample. 😦