The Hut has a Buy One Get One Free offer on Disney Pixar DVDs and Blue-ray at the moment. There's also free shipping on orders over £10, so you should get that almost automatically. Some of the movies are also discounted besides the BOGOF offer.
First off, don't assume the prices here are the cheapest, because they might not be. Compare what you want to buy with an outside source, like Amazon, because it may not end up cheaper. However, the BOGOF offer may well tip the scales.
I was looking for Tinker Bell and the Secret of the Wings recently as it deals with Autumn and the coming winter and so on, so it's quite seasonally relevant. It's currently £12.99 at The Hut, reduced from £15.99, but still more than the £9.87 at Amazon.
However, when you add another movie - say Peter Pan - which is currently also £12.99 but reduces to zero (either one might), then the fact that it is £11.10 at Amazon makes that more expensive, since the two together at The Hut will be £12.99 instead of £20.97 at Amazon.
Seems like a great opportunity to freshen up the DVD cupboard.