Play.com posted is a pricing chart for the upcoming games 3DS games. They currently list two titles at £24.99 (about $40.00 USD). While some may quickly write this off as a place holder, Play.com actually does have place holders without prices.
The 3DS does offer a lot more than iOS platform, so it's expected that the games would ask a higher MSRP when compared to games on mobile platforms, such as those on iOS. But when iOS has a typical $20 max price for games, do people (parents) really want to pay upwards of $40 per game on a mobile device.