Play are selling "Dragon Ball Z: Goku Densetsu" for the Nintendo DS for £9.99.
You can get cashback through the usual sites (e.g. 5% Quidco, making it just £9.49)
The next best price seems to be £12.95 from dvd.co.uk.
Dragon Ball Z: Goku Densetsu for the Nintendo DS is an all new DBZ experience unlike any other, combining strategic card-based gameplay and role playing elements to deliver a game that is easy to understand but hard to master. Players' progression is determined through their use of the cards to evolve characters, strengthen moves and create new moves.
In the game, cards are marked with eight types of actions, eight power levels and eight guard levels for a total of 512 possible combinations that will determine progress. Players are dealt five randomly selected cards to play with each card denoting one of eight types of actions. The intensity of special attacks will increase as the game progresses and multiple cards can be played together to power up attacks and enhance guard levels for super combos. While the game will progress even if players do not choose the best cards, strategic players will be able to unlock more surprises and become true masters. Dragon Ball Z: Goku Densetsu also supports wireless battle for up to 4 players and includes a game sharing mode.