Isn't the free trial a way for users to continually get content for free?  It seems that once a trial expires, a user can click use trial and start a new one.  Is this configurable like once and done.

If you can manage security roles, you should be able to handle this. Create a role for "Has used a free trial once" and then don't permit a new free trial for people in that role.

It might be that you can handle this with Datasprings Dynamic Registration module.