Most Nintendo 3DS titles will be at $40 dollars, but two titles have been listed as high as $50.
The list Gamestop gave to its customers who pre-ordered the handheld gives projected release dates for 26 titles, with the 3DS remake of The Legend of Zelda: Ocarina of Time being, according to GameStop, June 2nd, 2011. Only Dead or Alive Dimensions and Samurai Warriors Chronicles are set for release 12 days before the 3DS, and are listed at $49.99.
Gamestop seems to have confirmed Ocarina of Time for a June 2nd street date, though Gamestop has been unreliable before so it might be best to take that date with a grain of salt. The other titles are either unconfirmed, or have no word from the developers.