goHastings offers the used Nintendo DSi Handheld Game System in Matte Blue, model no. TWLSSBA, for $89.99. Coupon code "dealoftheday" cuts it to $45. With $2.28 for shipping, that's $33 under the lowest total price we could find for a new unit and the best deal we've ever seen for a DSi. It features dual 3.25" screens and inward or outward facing cameras.
Note: No warranty info is provided.