At GDC 2010 this week, Sony showed off the PlayStation Move, a copy cat to the Wii remote and Nunchuk for the most part, calling it the "next generation of motion gaming". The only difference really is the PSMove uses the PlayStation Eye camera and the Wii doesn’t.
The PlayStation Move starter kit will be under $100, so $99.99 I'm guessing. What’s in the kit? A PS Eye, a controller, and a game, the Nunchuk or “Sub-controller" will be sold separately as Nintendo did with the Nunchuk. It’s going to be pretty costly to get enough for a family of say 4 to get in the games together.
Let’s say the PSMove kit is $90, the standalone Move remote $50 and Sub-controller $20. So for 4 people to play together could possibly cost you: $90+$70+$70+$70 = $300 in total! $90+$70+$70+$50 = $280
[Update] The price was adjusted above because it turns out, only 2 Sub-controller’s are supported since the PS3’s Bluetooth support is limited to only seven connections. Four PSMove controllers can connect to a PS3 at one time allowing 4 players to play but only two players if the sub-controller’s are used, two PSMove Controllers and 2 PSMove sub-controllers, because of this Bluetooth limitation.
Now for Project Natal. We know nothing about price at this time but it’s rumored to be under $100, at one time even rumored at $50. The difference with Project Natal is that only one item is needed for the 
whole family to enjoy, the Project Natal sensor device, making your body the controller. Separate controllers are not needed to start Moving with Project Natal. The cost to Jump In will be a lot less then the PlayStation Move if you consider buying for the whole family and if indeed under $100 for Project Natal then possibly cheaper than the initial PlayStation Move kit.
Being that Project Natal uses only your body as a controller, it will be easier to get a non-gamer Moving, so I’m banking on Project Natal to out sell the PlayStation Move by Millions!
