It all depends on the time you got it. If you got it within the last 30 days and it is unopened (which is unlikely) you may return it for the full price, which is more than that of a DS Lite, and you can buy it in the store with some extra money. If not, you will have to trade the DSi in as used, and you will probably get around $80 USD, and you will need $99.99 USD to buy a pre-owned DS Lite and it will cost $129.99, and you won't have enough money.