Nintendo DSi purchase limit policy - As you may know, the Nintendo DSi is in great demand, and there are shortages of this product across the U.S. In an effort to provide as many customers as possible with the opportunity to purchase a Nintendo DSi, we are limiting the total number of Nintendo DSi units that can be purchased. As a result, each household may only purchase three Nintendo DSi units.

I would guess there's pretty great demand, seeing as how both colors have already made it into Amazon's top 10 purchases for video games.

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