I saw this on hotukdeals www.hotukdeals.com/deals/nintendo-dsi-a-selected-top-game-in/769848. If you buy a dsi for £97 you get £22.97 off of the following games Club Penguin 2, Lego Harry Potter, Pokemon Heartgold and Toy Story 3 so it will effectively cost you £99 (unless you go for the Pokemon game as this costs £32.97 instead of £22.97). Heres a link to Asda online groceries.asda.com/asda-estore/specialoffers/linksavecontainer.jsp?promoId=ls62381.
Online only black is available but instore all colours are included. Be warned that instore this offer price isn't advertised but it is coming up at this price when you pay. I've just bought a red dsi with toy story and a metallic blue one with club penguin, both at £99 each (ready to put up for Xmas 
). I've been keeping an eye on prices for a while and this is the best deal around. Hope this helps someone!