I do not now, nor ever have, nor have any intention of ever, using paypal for anything. Ditto for CCBill.
I suggest that you
-1- set up a secure site
-2- Generate a reasonable password
-3- Accept payment via postal money order
-4- Use that payment to activate the user's account
-5- Allow the user a window of X-Amount of time
During that window of time (A week ? A Month?) the user may download the clip.
You get the money, he gets the clip.
I believe this has been suggested at least once before; if not by me, then by someone smarter than I.
At this moment, I still have no idea of why no one is practicing this concept.