PowerPlayDirect is selling "Disney's Enchanted" for the Nintendo DS for £12.49 (inc Del.)
With the attached voucher the price is reduced to £12.24
You can get cashback on this through the usual sites (e.g. 4% Quidco, making it just £11.75)
The next best price seems to be £14.93 from TheHut.
Disney Princess: Magical Jewels for Nintendo DS invites players to play as their favourite Disney Princesses in an enchanted adventure. Players explore the game at their own pace and skill level to recover the Magical Jewels and restore the magical power of a kingdom. In a magic-filled romp through locations familiar to Disney fans, players experience the excitement of interacting with the environments through the Nintendo DS touch screen to solve puzzles and tasks that help each Princess on her adventure. A tiered design provides an accessible play experience for the younger player, yet also provides layers of challenges for older players. Multiplayer modes allow the player to have a friend join the fun.