"Pair @ Go" Mega Pack accessory pack for the DS Lite. Includes the following:
5 Game Cases (all black in the one I bought)
Spare Li-on Battery
AC Adaptor (3-pin mains to USB adaptor with USB-->DS cable)
Mini Screen Wipes
Considering that this includes a spare battery it seems like a decent deal to me. Original price shown as £19.99, down to £12, then "Half Marked Price" sale. I bought one, and there were still some left (Fosse Park Leicester branch). I presume other stores will potentially have some? The quality is decent enough, even at the higher prices!