It looks like Google is underplaying the free offering of the Google Apps for mail, calendar and all the other stuff. Probably, they’re going to stop offering this. I found this link http://www.google.com/apps/intl/en/group/index.html on the web which worked today. Not sure if it’s going to be there for ever.
Alright, ride the wave while it’s there. I did not see free request for additional users either, so try stating the number of users needed to the expected one upfront.
Good luck!