Not really.  Facebook does NOT charge by click nor by lead.  It’s a pay-by-impression only platform.  You’re paying for the number of times your ad is shown to people.  It inherently limits the amount of times a single person can see an ad, but some people will see your ads multiple times, some only once.  People should see your ads multiple times though when possible.  It’s a good thing - that creates brand awareness and trust and of course this means sometimes a person will ‘become a lead’ more than once.  Of course, our retargeting strategies are specifically designed to show your ad to people more than once too but we intentionally exclude leads from the retargeting.