[plant42]

I signed up before the change to being a paid service, so am not paying unless I go over the 10 account limit.

Now its $5 per account. An account being in Googles own words:

"We consider a user to be the same as the number of distinct email inboxes you need. One user can have multiple email addresses, and a domain can have multiple aliases – these are included in the price for each user."

Check out all the info you need at: http://www.google.com/enterprise/apps/business/pricing.html