The Hut are selling "Animal Crossing: Wild World" for the Nintendo DS for £14.43 (inc Del.)
You can get cashback on top of this (e.g. 5% Quidco, making it just £13.74)
The next best price seems to be £22.99 from SHopTo.
Welcome to Animal Crossing: Wild World - Your world just got a lot bigger...
Get ready to start a new life! Whether you want to decorate your home, catch bugs or fish, join in on special events or just chat with the locals, there's always plenty to do! And now you can share the fun with friends near and far using either wireless communication or the Nintendo Wi-Fi Connection. Wireless router or Nintendo Wi-Fi USB Connector and broadband access required for online play.