Are these courts free to the public or is there a fee you have to pay to use the courts?

There is a fee - for playing matches it comes out to $3 per person, per hour. For singles matches, I usually reserve a court for 2 hours and pay $12. You can also rent a ball machine but I don't recall the price. Be sure to reserve a court in advance since there may not be any available if you just show up. If you don't want to pay, other nearby public courts that are free are at Sweat Mountain Park, Fuller's Park, and Skip Wells Park (which are all first come first serve).

Fee to use.

Ball machine rental is $12 plus the $3 court fee. Cobb has 6 tennis facilities that are fee based and several that are free.