Was in Royston Tesco today and I noticed they're doing the Ratatouille/Pixar Shorts 'Limited Edition' 3 disc DVD boxset for a rather bargainous £9.99.
I'm assuming this is nationwide, given the standard pricing label. They had the typical price comparison against play.com on the label also, where it's £23.99.
Next cheapest I could find was £12.99 online at HMV. It's £27.49 at Zavvi and £19.81 at Amazon.