This is kinda tricky. There are smartphones that have weaker hardware than NGP and costs about $400-$600 without contract.
However, if the NGP price is in that range, it will sell slow at the beginning. IMO, $350 would be a "good" price considering the stuff it has, and still it's a good chunk of money when you consider it as a "portable gaming" device. --- http://www.backloggery.com/darkaura http://www.rfgeneration.com/cgi-bin/collection.pl?action=profile&name=Dark Aura&folder=Collection
250-300 is def. going the be the best bet. Anything more then that for a handheld is going to do nothing but lose money. If they plan on competing with the 3DS then there going to keep a price range similar to it because there not much else it offers that the 3ds doesnt. 3g is cool but not something a very large % of ppl who buy it willl care about.