Can I set a limit of number of attendees in an meeting?

Yes. 

In order to limit the number of attendees that can attend your meeting, you must require Registration during the set up process. 

In the registration process, after choosing the information you want to collect, Fugent gives you the option to limit the number of attendees.                                                                                                                                 
To allow an unlimited number of attendees, set the number to 0 (zero). 

Keep in mind that if you are limiting the number of attendees, a small portion of your registrants may not attend the meeting after registering, so you will want to set your Max # of Attendees a little higher. 

If you would like to set a limit of attendees for a previously scheduled meeting, go to the Options and select Manage Registrations.