Adding users as 'view only' under Professional Edition

Adding users as 'view only' under Professional Edition

Hello - 

seeking help on adding a user under the Professional edition.  Under the FREE edition I was able to maintain 2 additional users as standard users.  Once I signed on to Professional, I anticipated that the standard users would not be additional cost, yet they are.  Is there an option or a way to set up one additional person just as viewer with no additional capabilities?  Executive Directors should be able to at least look at activities without being considered a 'user'.  Help please on how to best achieve this?  Thank you!