add a simple buy now button to listings

Hi please let me know if anyone can help me with this, I would like each listing that’s added also display a buy it now button, that when clicked on by a registered user it ends the item (if ending the item isn’t possible then this isn’t that important for now), and lets the seller know who’s has brought there item. giving their name, email etc…

they can then contact the buyer to arrange payment. Is there a simple way to do this??

I don’t see something like this being to hard to achieve could anyone help??

Ideally it would link to the sellers paypal, but for now just a simple buy now button that lets the seller know whose clicked the buy it now would do.

please let me know if anyone can help.
thanks