The question is why sell it in the first place? For love, money, a great career? I think it's pointless when you can become omnipotent. You have the power to get anything you want in life but it takes a lot of will.
Definitely interesting information here. It is nice to know you cannot sell your soul. I hope that is true. Sometimes I wonder if it exists at all. I guess it is more a faith thing. I would like to summon these spirits or demons for help. How do you offer up the gift to a spirit that has helped you, as an example the bowl of cinnamon that the user posted in this very thread? How exactly do you go about doing that? I read of Saints and the offers that people have offered up to them. Flowers, sweet white wine, Florida Water, praise. How do you offer up the physical things is what I am wondering? Also read for catholic saints how donating to catholic charities as part of praise. I like that idea.
Not everyone has the soul. From a research to abducted people only the 20% of humanity has the soul. The alien or entity how you would like to call it said through hyposis that a human in 90 has the soul so.. I think that you don't have the soul cause you have no reaction of protection. Who has the soul first needs to be RH negative in the blood test, and a soul-being is not afraid of death, doesn't care about money and power, and knows the real meaning of love that has nothing to do like romantic movies and songs.
As many have said already you can not sell your soul. You can dedicate yourself however, make a pact, offer up something in an agreement for something in return. These however must be reasonable things, tangible.
Indeed looking into the daemon might help you out. If you do take this route make sure you learn what your dealing with and how to deal with it first. These entities are not to be played with or taken for fools, the are known to be quite cunning. It would seem as well that much like us every one of them has their own personalities. Something they have in common is that they like to be treated with respect.
There are many different books that you can look into and many different views on them. Like I said make sure you know what your dealing with. Also keep in mind that invitations are also a way to call on this type of entity with out having to summon it.
I have done a lot of research on these entities and would be happy to try and help answer further questions. Perhaps point you in the direction of some good literature.
My dear sweet child, you are lonely, I. Understand that. But to actually want to "sell your soul " is not the answer. There is someone for everyone, and your "other half " is coming. You must have patience. Love is not easy, so slow down. Your in a rush and love doesn't happen like that. Maybe things are bad at home, maybe you feel unloved, but you are loved! We love you. We are here for you. Maybe you just need someone to listen while you talk. We're here!!