Man is the owner and auctioneer of his own heart, and it is most definitely for sale. 

He puts it on display at the market ready to be sold to the highest bidder.  The bid is his own lust which is never quenched and never enough. 

Once sold, it is forever mortgaged and carried away to a land of enslavement.  The only prospect of freedom is the Soul. 

The Soul can purchase the heart and bring it back to the man, but only with permission from the original owner.  ...Most folks have sold their hearts at the slave auction and misplaced their Souls during the move.