Inform users of "Logo'd Gift Cards" for Premium Membership
When you click on Premium Membership it suggests that people who don't have PayPal or a credit card should ask a friend/relative to buy a Conquer Club gift certificate.
Another option is a gift card with a credit card logo.
I buy VISA or MasterCard gift cards at the grocery store and use them for online purchases. It worked fine for Conquer Club. You pay a 5-8% premium, depending on the size of the card, but since I have no intent of connecting PayPal to my checking account, it's worth it for me.
YMMV, but I think it's an option that should be mentioned next to having a friend buy it.
Caveat Emptor: I had trouble using American Express gift cards online
I have no affiliation with any credit or gift card company.