There are 242 in total: 120 Power Stars and Grand Stars, 120 Green Stars, and two in the final level.
The answer is in the title...
There is currently no Super Mario Galaxy 3. If you mean Super Mario Galaxy 2 there are 242 stars.
Super Mario galaxy 2 can be played as a 1 or 2 player game. You can play with 2 players simply by plugging in another wii remote. When you play with 2 players, player 1 steers Mario, and the other a luma. The luma can stop enemies in their tracks and then spin to make them fall over. Player 2 can in addition pick up coins and starbits. Also if both players point at Mario at the same time and press the A button at the same time, he does a super jump.
42
$40
Super Mario Galaxy 2 will be released in the US on May 23rd 2010.
6 stars
to be honest......none
there are 49 Galaxy's including the grand master galaxy
8 files of choice.
Billions and Billions ,then, infinaty
7 times you must lose a life in the galaxy and then the super guide engages.