Potentially a dumb idea, but to satisfy credit card spend requirements for frequent flyer points, can't you get a friend or family member to send you a PayPal invoice for something arbitrary, pay it with your credit card, and they withdraw the money and give it back to you?
I'm guessing there'd be some fees involved but it would be a lot less than the spending requirement.
Why not just buy on their behalf and get them to pay you back whichever way is convenient.
As long as they are trustworthy.