WHSmith are selling "Shrek The Third" for the Nintendo DS for £11.99.
Free delivery until 10am April 21st.
You can get cashback through the usual sites (e.g. 10% Quidco, making it £10.79)
Next best price seems to be £14.83 from Woolworths.
Normally film tie-ins aren't very good, but this has a Game Rankings score of 70.2%.
SAVE FAR FAR AWAY!Take control of your favourite Shrek characters with the Touch Screen, microphone and more.Play through the whole story by yourself or with your friends in co-op wireless multiplayer.Adventure through 16 levels from the movie and beyond.