They couldn't have opened the credit card without obtaining your SSN, so you had to have provided that to them. They would have also had to have had you sign a terms of service for the card. You don't provide your SSN for a Good Sam Club Card, so they wouldn't have had that on file. Did you provide it at the checkstand?
As for the rates, it is $27 per year, but if you sign up for 2 years, it is $25 per year for a total of $50.
If you did not provide your SSN and/or sign anything, you can simply write a letter to the Credit Report Agencies (make sure to send it to all three) and explain the circumstances and that you did not provide your SSN or sign any TOS, that you were not informed you were applying for a credit card, and that they ran your credit check and/or activated the credit card without your permission. That should get them (both the credit check and the card) removed from your report completely.
If you did provide your SSN and/or sign a TOS at the checkstand, then it could be a bit more difficult. This is why you should ALWAYS read EVERYTHING before signing anything (even at a checkstand). There was a study done a while back and people signed away their children, etc., because they didn't read the TOS for website registrations - no matter how inconsequential it seems READ EVERYTHING BEFORE SIGNING.