Starting on December 6, 2012, Google will no longer offer new accounts for the free edition of Google Apps. Google Apps free edition is sometimes referred to as "Standard Edition."
If you already have the free edition, you can continue to use it for free. This change has no impact on existing users of the free edition. (http://support.google.com/a/bin/answer.py?hl=en&topic=29190&ctx=topic&answer=2855120)
Google Apps was first launched to allow 200 free users, then it shortly changed to 100 users limit. In January 2009, the cap changed to 50 users. In 2011, Google further reduced the limit to 10 users. Now, on December 6, 2012, Google discontinue Google Apps Free Edition. (http://en.wikipedia.org/wiki/Google_Apps)