GameStation are selling "Gunpey" for the Nintendo DS for £4.99 + £1.00 Del
You can get cashback on this through some sites, but make sure that they pay out for new games (e.g. TopCashBack gives 5%, where as Quidco doesn't seem to give anything).
Next best price seems to be £9.99 from ShopTo.
Gunpey is another one of those magnificently-conceived and thoroughly addictive puzzle games from Q Entertainment - the developer responsible for Meteos and Lumines - with a bit of music-making thrown into the mix for good measure.
Gunpey's gameplay consists of rows of panels climbing upwards from the bottom of the screen. Players have to flip and move to connect lines inside the panels. When a line of panels reaches all the way from left to right, the panels explode, thus making room for more. Of course, if the panels rise all the way to the top of the screen, it's game over. Every move made by the player changes the in-game music, alowing skilled players to eventually deliver their very own musical performance. There is a selection of game modes available, such as Break Rule, Time Attack and 10X10, where the number of panels onscreen is doubled. With the the DS version, players can launch special attacks to temporarily disrupt their opponent's game and use the Sound Sets and Patterniser to create their own unique musical compositions.