I was confused about this too. The DS lite is the new version of the DS. The DS lite has a brighter screen, is thinner and looks like it's been designed by apple. So the DS lite superceeds the DS.
I got mine in Smyths. The assistant did some jiggery pokery with tokens and stuff, so I got two games and the machine for €200. That was a few months ago, so I'm sure you can get a good bundle of some description. There are always offers on.
As for the games, I've started buying the used ones (about €10 cheaper) with no problems.