“As long as you are already creating a fully rendered 3D world, all you have to do in order to create the 3D visual effect is to capture the same images with two cameras, one for right eye and the other for left eye. From a development perspective, it actually does not make much of a difference in terms of development costs to create the 3D visual effect. On the other hand, because the visual capabilities of Nintendo 3DS are more powerful than the existing Nintendo DS, if you are going to take full advantage of the graphics capability of Nintendo 3DS, the development cost is also expected to rise. Therefore, if developers decide to try and maximize the graphical powers of the system, then the cost would be more expensive than what it is currently for Nintendo DS and may potentially approach the cost of developing Wii software.” – Satoru Iwata

Prices are already reaching the $40 mark for top-notch DS games, $50 or maybe even $60 for the quality of 3DS is not out of the question for me.

Link