How much should I sell this Nintendo Dsi and DS game collection and other accesories for.?

First of all, you should definitely be able to get enough for a 3DS off of all that. If you don't, there would have to be something wrong with everything. I would go onto eBay and put it on an auction and buy it now. I would start the auction around $350, that way if that's all you got for it you would be able to get a 3DS and have $100 left for games and accessories. Put the buy it now around $500 or the original price for everything.