I believe you're foiled by ebay's TOS anyway -

If your (or someone else's) soul doesn't really exist, there's no way you could deliver it, and so you fall foul of the conditions of listing (not to mention trading standards laws):
5.1 Listing Description. You must be legally able to sell the item(s) you list for sale on our site.1

But if the soul does exist, it must be part of you (or them), and is a prohibited item:
Humans, the human body or any human body parts may not be listed on eBay. Examples of prohibited items include, but are not limited to: organs, bone, blood, waste, sperm, and eggs. You may not include such items as a gift, prize or giveaway in connection with an item listed on eBay.2

'And I'd have gotten away with it too, if it wasn't for you meddling lawyers!'

1 - http://pages.ebay.com/help/community/png-user.html
2 - http://pages.ebay.com/help/community/png-remains.html
source: some random urban legend that I can't track down