In regard to the PayPal $1000 limit, I understand the American Express Co.'s stance on the issue: since one might use PayPal to essentially withdraw cash even though it posts as a purchase, it becomes a higher risk for AmEx. And sending cash in large amount over a system that is supposed to be used for micropayments should definitely raise some red flags for a transaction. In the case of paying for a laptop bought on eBay (something I would never do, since it might be defective, stolen, etc.), you could always send $900 from your Amex card, and the remainder of your balance from a different mileage- or points-earning credit card.