There's an offer on Groupon (New York City for me) for 3 Redbox rentals for $1. I bought mine through the SwagBucks daily deals section. I clicked on any offer for groupon, then I made sure the Trial pay offer was at the top it should look like this:
It's a banner at the top of all the groupon pages once you get there. The offer is listed for Abilene Texas, however there was a link at the top of my NY City page, saying click here for the Red Box offer. That in turn took me to the Abilene, TX groupon offer. I did buy it. I haven't received credit yet. I do have screen shots and my confirmation email.
Will Trial Pay honor the offer listed at the top of the page? We'll see. It's only a buck if you want to give it a try.