I think your best bet would be a "pre-paid visa card". They are inexpensive and a better way of using money safely and anonymously. They can be picked up from most places like Walmart, Walgreens, your even your local post office. You can also get them in Visa, Mastercard and many others. But I am not really sure on their policy here on using prepaid visa cards. I use them myself from time to time but all you do is buy one. Load up money on it. And then add it to your account and hey presto, you got a payment method. And then when you want lindens just load your card up with cash. Or you can do what these guys said and earn money. It's alot hard and takes longer but it's a way you can get L's without spending money.