Free movie rental from Chromecast
To celebrate the second birthday of Chromecast, there's free rental on a bunch of films, so how do you get at them? Well, open up Chrome on your desktop and through the Chromecast extension (install it if you haven't), visit this website and 'redeem all offers'.
You'll then need to click the Google Play offer in the top corner of the page, and boom! You'll have a rental voucher for free. It can be applied when you checkout any film on the Play Store.
Now, it doesn't work in all countries, but seeing as it is such a simple process, you may as well see if it works for you. It might tell you that you've "redeemed the maximum number of free rentals", so it seems there's a limit on the offer too. It has worked for some UK-dwellers.
HD movies are available too, so knock yourself out with some free films.