ChoicesUK are selling "Rampage Total Destruction" for the Nintendo Wii for £9.99 (inc Del.)
You can get cashback through the usual sites (e.g. 5% Quidco, making it just £9.49)
The next best in-stock prie seems to be £13.99 from Zavvi.
Monsters On The Loose!
Get ready to roam, rage and rampage your way through cities of the world destroying all in your path George, Lizzie and Ralph are back along with 37 other monsters you can collect and play as. Wander through 3D neighbourhoods trashing everything in sight as you uncover hidden monsters and power ups.