Amazon Instant Video offers rentals of Whiskey Tango Foxtrot in HD for 99 cents. (Google Play charges the same.) That's $5 off and tied with our mention from two weeks ago as the lowest price we could find.
iTunes offers a selection of movie rentals in digital HD for 99 cents. (To see these deals, open iTunes on your computer, click to the "Movies" page, and scroll down to "What We're Watching: 99¢ Rentals".) A couple of best bets: