There typically isn't exclusive offers. I would say around every 2 months, they have like a monthly offer that you have to register for. Anyone is eligible for these offers, but you have to register for them for some reason. The only exclusive offers that I know of are reload bonuses, I believe those happen rarely and only if your account has an empty account. On the Cardschat freerolls I'm not sure what you have to do, I am sure there are instructions on how to enter them.