I think you get free practice if you pre-register for a race. So you get the Saturday before the race to practice. You can have unlimited practice times and days when you become a member since you will get a key to the entire field.
Currently all the races I see on their site has a $5 discount to members.
I will be racing a B4 hopefully with my mod motor. And currently only the TC3 at HobbyCentral, unless I can modify it and be allowed to run it on the dirt oval. I have read several places about TC3's bringing competition to other nitro dirt oval trucks.