I just had a look through what's available to watch on the Flipps app hoping to catch a free Christmas movie or five, and saw Frozen on there to stream for free, and in HD too. All you need is the app and a (free) Flipps membership. Great if you have Frozen-mad kids, a smart tv or streaming box, and a hangover on Boxing Day.
Also available in SD for free. Lots of other Christmas-themed movies available for free as well - The Grinch, Polar Express, Home Alone 1-4, The Santa Clause 1-3, A Christmas Carol (Jim Carrey), Jingle All The Way and many more. And almost all are in HD.http://www.flipps.com/