Working on something pact and contract related recently, I have came to notice how , even among the occult authorities there is a constant debate on whether a pact with a spirit can be a contract as well. They have a good point there, in my humble opinion for I highly differentiate pact with sprit and contract with demon, as can be seen from following excerpt from the work of mine I have mentioned at the beginning of the text. I wanted to share my findings as well as attain possible new, hence the survey, as shown bellow. Now before I add the mentioned excerpt I want to note two things, one being a question really
1. Do You personally believe in pacts with the Spirits? What about contract with Demons? Do You believe in possibility of actual physical or even non-material contract? Have You ever had or heard of similar experience? Would You Yourself agree that pact and contract with a spirit ( latter mostly referring to demons ) are two things that despite sharing some basic similarities are different , both in very methodology and results? Could pacts be part of tradition and folklore , whereas contracts could be High magick ( influenced by Judeo Christian religious teachings ) bound concept? Taking time to read and answer, would be really appreciated, as to me its a poll, a part of research possibly to be include in final version of text I am working on. Therefore, great Thanks to anyone that answers in advance :-)
2. I wish to thank Miss Artemissia a member of this site and a dear friend for her help with information on Vila Samodiva entity, indigenous to her country folklore
*please not e that the excerpt is just a part of complete text, as such is missing some examples of pact making and methods of , tradition bound or otherwise, influence and appearance in culture, popular culture etc. I chose the part that deal with pacts with chthonic spirits in Eastern Europe and part dealing with Contract making according to Christian and Medieval occult system of magick
In Balkan Peninsula folk magick, pact with all sort of natural and chthonic spirits are so very common, that I could not possibly elaborate even just the common ones here. Hopefully , I might sometimes dedicate a longer, more elaborate and comprehensive blog post to it. I shall howeve r, mention few examples here. In Serbia, Montenegro, Bosnia and Herzegovina, parts of Croatia and Romania, it is common to make pact with a chthonic spirit called Tartor which is described as water De*il , though called so most likely due to Christianization, much like its case with Black man of the Crossroad in Hoodoo. To make a pact with it, witch must enter cold water naked, with untied, loose hair and pledge to loyalty and service. Sometimes , this is not enough , for Tartor may ask for Young pretty girl, which the witch or Cunning women shall provide. The girl enters river naked, with loose hair as well, and is often forced to intercourse with the mentioned spirit. Pact with this spirit is also the answer to a deadly condition, when he fascinates Young men that accidentally fall asleep near river in bad hours of night, or near the watermills , a cultic place in Balkan traditional and folk witchery. In such case cunning men ( or women lol ) shall take the young men to make a pact with the spirit, and so to be saved from drowning, in which would the condition otherwise result. Similar is the pact with Smeu, a parasitic dragon man creature of Balkan folklore, with whom girls or boys ( for he, dragon Smeu is androgynous and can take on gender which he feels like ) can create a pact, where he does them favors and get sexual service in return. Unlike Tartor, despite his harsh nature that leaps more on malevolent side, Smeu ( also called Zmei, Zmeu etc ) is not seen as De*il nor identified with it.
My friend Artemisia, has recently shared with me some brilliant information on Fae lore in Bulgaria, among other including examples on how are pacts made with Fae there. In Eastern Europe folklore, pacts can be made with fae Folk , and are usually less threatening and dangerous in nature than pacts with chthonic or demonnic spirits. Typical examples would be pacts with Diva Samodiva as known in Bulgaria ( known as Vila in Romania, Serbia, Macedonia, Montenegro and some regions of Croatia ) which is made in more ways than one. They can brother ( verb, become brothers with ) Young man who would show themselves as worthy by respecting Nature and protecting it, respecting forests , meadows, plants animals and fighting for them. A less humane way would be stealing their veil while they bathe and returning it only for a favor, or for marriage as Young man of Balkan would do, for these Fae are extremely beauty and have enchanting, dazzling eyes that can mesmerize any man  .
In Eastern Europe, folk songs, and tales speak of sacrifice bound pact with River Fae and Water De*ils , where an animal or even kid in some cases would be offered as part of pact, and in return the mentioned spirit would not torment people and village. Today its more often to offer green branches, bread, rice, or wheat as tribute to all sort of River entities, while either evoking them or simply appeasing. Its still perceived as form of pact, often done repeatedly over some time.
Now I will be mentioning later in text how did the Balkan folk perceive pacts with actual de*il and what was needed for such.
Contract with the Wicked one in occult and Medieval Christian tradition, and on Dr Faust
According to occult teachings, one could acquire a contract with the fiend, via means of Higher magick work, such as Invocation and Evocation of spirits. Christian theology agrees on such , although perceiving whats called as Higher magick as demon worship, sometimes.
In her encyclopedia of Witchcraft, on 194th page, Rosemary Ellen Guiley provides all alleged terms those that wanted pact had to fulfill, among other, denying protection of Christian Gd and Virgin Mary, mocking of baptism, foreswearing of old name , getting new godfathers renouncing the old ones etc. 
In Eastern Europe, particularly in Balkans, according to folk tradition there are various methods of entering a pact with demon or making a contract, all sharing some common traits, among other not bathing for a specific amount of time, not praying and not cutting hand nails for 40 days , sometimes less. After that the person was to visit chtonic places, such as Crossroads, Watermills , or under large dead tree trunks. Then its suggested that the person in question invokes demon with personal invocation that usually included renouncing of all good and pledging to service evil. In exchange, most often great occult powers were received.
The practitioner, willing to sell their soul for favors, power, money or whatever, would often used the demonic signatures, or sigils, to contact the demon or the Wicked one itself, and the rest would go as any bargain. Sometimes these items ( sigils ) needed for contact or acquiring more occult power were given to practitioner by spirits themselves, or shall I say demons, some of which were obtained from classical grimoires such as Goetia, The Lesser key of Solomon or The Great book of St.Cyprian.
The person in subject, that wanted a pact, had to renounce Christian Gd , or If they have not been Christian, pledge to loyalty to the fiend. Contracts would then be made, in actual physical form, one taken by the Wicked spirit and one reserved by practitioner.
Typical examples of such deals would be that of Louis Gaufridi ( 17th centry Priest ) and the Wicked spirit himself. Louise was allegedly given power to fascinate, bewitch , enchant and seduce by blow of mouths.  The Malleus Malleficarum text speaks of such pacts with the fiend, particulary among witches to procure spending occult powers and abilities, which they accordingly used to wreak havoc and cause misfortune, as suggested in mentioned work. Such people were also said to have been branded by means of senseless spot on their skin, which could not be affected by pain or physical injuring, This was taken as diagnostic criteria indicative or witches that consorted with demons, most commonly Wicked one in person.
However other demons have been keen on such pacts as well, even lesser one. Peter Stubbs or Stumpp ( also spelt Stubbe ) admitted being given magickal belt, that enabled him to become man slaughtering and devouring beast, by will, by an incubus demon.
Sometimes Dev*l shall send other demons to close the bargain in his name . Like in the famous legend about Dr Faust, who feeling unfulfilled with the knowledge he had, offers himself to the De*il. The Wicked spirits sends an emissary instead, called Mephistopheles who nevertheless closed the pact with Dr Faust, that was to end in De*il himself obtaining the poor mans sould nevertheless. Many believe that, at least the protagonist of the legend ( and latter of the Goethes novel ) was an actual, once alive person. However the identity of true Dr Faust remains vague, although speculations and theories of it exist. Its widely believed that the figure was actually Dr. Johann Georg Faust , that lived at the end of fifteenth, till first half of sixteenth century, and was known as magician and alchemist with an degree in divinity from Helidelber g university. Other common belief is that ( one of the many possible sources of the legend ) it was Johann Fust, Johann Guttenbergs business partner. Be it as it had been, the legend is alive even nowadays nevertheless, spreading its influence and warning even to pop culture, and is present in jargon speech and phrases, Faustian deal being one suc h example, denoting a bad barging/deal, where the price heavily surpasses gain, and therefore is no t really worth of same.
END OF EXCERPT
Credits and references as used in Excerpt
 Written contribution by Miss Artemisia , a dear friend and knowledgeable magick practitioner
 According to Rosemary Ellen Guiely book : http://books.google.me/books?id=NHosWhaeWDQC&pg=PA194&lpg=PA194&dq=louis+gaufridi+pact&source=bl&ots=Jj9-PIAhPg&sig=NUHI7duCRly3aeJm29T-FJYRuws&hl=en&sa=X&ei=9tQRT9qFC6XP4QTp5ZjCAw&sqi=2&redir_esc=y#v=onepage&q=louis%20gaufridi%20pact&f=false
 According to same source as listed under