Yes, Jellyrolls is like a bar and I believe you need to be 21 to enter (no kids allowed).
Yes, there is a cover to get in. We were there about 1.5 years ago and I believe it was around $5.00 to get in.
I believe I read on another website that the doors open at 7:00 and the show starts at 8:00.
It is alot of fun. Enjoy.
Linda