PayPal "Buy Now"

I was wondering, is there a way via paypal, to make a one off "Buy Now" button? Like if you want to sell an account for an A/W, you could have the user/pass in a .txt file on a file sharing site, and the buyer would have to click the buy now thing and go through the usual process, but anyone who did that after the original person couldn't go through with it

 

Go to PayPal.com > Merchant Services > Buy Now Button...

you must be logged in to PayPal to see the Merchant Services tab.

 

You couldnt block another person from doing it.

Although you could make a donation button.

 

Moved to Assets and Investment Discussion.

 

I know how to make a buy now button. I want to know if it's possible to make a one off one, and if so, how