My Momma used to say, "When a deal is too good to be true, then it is normaly not true".
Best case scenario:
You safe 40 bucks.
Worst case scenario:
You lose 33 bucks
You gave away your credit card number with your SEC number
You gave away your real name
You gave away your real address
Possible 1 year membership?
I would ask friends, if they have experience with this provider before buying. And if you still want to take the risk, i suggest to use a second credit card for only these kind of things, not your real one.