Ds light is $50, Dsi is $70 and Dsi Xl is $100
Initially a 3DS costs about $270. If you trade in you DSI you get $75 off. Trade in DSIXL for $100 off. DS lite gets $50 off (if you were wondering)
about 60-70 dollars
in Australia if you go to game the 3ds costs $99 if you trade in a dsi XL console and any 2 ds games
no
yes
Depending on where you will do the trade, you may either get the 3Ds free or will have to pay a little bit extra. (Depends on their condition.)
yes, at Gamestop Trade your DSi XL and get $100 in-store credit toward the reservation of a 3DS, trade in your DSi and get $75 or trade in your DS lite and get $50.
No not even for a DS. A PS2 is worth about $20 in trade
The DS lite won't fetch much, only about £30.00/$40.00 top condition. Subtract that from whatever the cost is for a 3DS in your country.
You can not make your own 3DS. If you order parts of the Internet you can reassemble your own.
While you can't trade an older system for a newer one, you can certainly trade a DS/DS Lite in for credit at GameStop or stores like it.
Assuming that you go to a video game specialist store like Gamestop, or a place that lets you trade in games for cash (like Best Buy), *you can trade in your DS or DS Lite, but it will not be enough to buy a Nintendo 3DS.* You will need to trade in a lot of other games also, or save up some other cash too.* 99.99% certain*