Is there an age limit as to who can get in free on their birthday? & do you need to call in advance to get in free on a birthday?

The park entry is free, only you have to pay for the rides you want. So everyone can get in free either it's their birthday or not, and is no age limit, however please check with park management to avoid any misunderstanding

Admission is free for everyone, you only pay for what you want to do. If you only want to go to the arcade, then you only pay to get a card to load money onto. If you only want to ride a few rides then you can pay for them individually. Or if you want to ride everything you can purchase a pass at the front gate for about $45-$50. There's also gatorland onsite as well with live animals. So my advice is to go first and check the place out for free. Then decide what you want to do and that will determine how much you're going to spend. Birthday parties are a different story, but you can check their website for details. Hope this helps!

BIRTHDAY PARTIES!! Enjoy unlimited rides on all Go-Karts, Roller Coasters & Rides ALL DAY (Sky Coaster not included, but does qualify at a discounted rate) Birthday child receives FREE Fun Pass Special gift for the birthday child FREE Chauffeur armband for every child under 54″ tall 2-Hour outdoor covered table is included with minimum food purchase. Food Add-Ons menu available for download below. No outside food or drink except for birthday cakes. Gator Spot is included(Orlando location only) $39 / PERSON (8 PERSON MINIMUM

The entrance to the park is free for everybody, even the parking is free. You just pay for the rides and food. They sell packages for all day all rides for $59.00 or if you just want to ride an especific one just pay for it between $6 to $9. It's a great place and isn't crowded

Im not sure either, but you can get $5 off a day pass if you buy it from their website. And I think $2 off for Florida residence.

I don't know those rules. Well see if someone else answers.