In the UK, it dropped to £20 a lot of places then sold out everywhere instantly (this was around the 20th Dec), not been in stock at any of the 'big' retailers except Amazon since, though they didn't drop the price.
I got my copy from Wilkinsons of all places, last place it was in stock, for £15.
I see. It's still full price everywhere in the USA. I haven't even seen a sale anywhere.