Cheapest Nintendo DS
Best packages for the Nintendo DS: On a budget
The cheapest Nintendo DS is small, light, and boasts built-in Wifi. Check out this post by Tecca to learn more.
"The cheapest handheld in the budget range is the DS Lite, with a 3" touchscreen and battery life up to 15 to 19 hours. It weighs about the same as the DSi but is lighter than the XL and has most of the basic functionality they do.
The Lite differs from the DSis in that there's no camera or SD memory card slot, and you can't download games directly via the wifi connection. However, it does have one function the other two don't -- backwards compatibility. This gives you the ability to play older Game Boy Advance games, which are still available to buy if you hunt them down..."