From Longman Dictionary of Contemporary Englishsell your soul (to the devil)sell your soul (to the devil)BAD BEHAVIOUR OR ACTIONSto agree to do something bad in exchange for money, power etc → sell
Examples from the Corpus
sell your soul (to the devil)• A whole week in Paris at Easter seemed to her something for which she would willingly have sold her soul.• He doesn't accuse us of selling our souls.• If he were mine, I would rather sell my soul.• Timothy was agonising over her, when Honor West would have sold her soul for a single kiss from him.• The fact that we would literally sell our soul to Continental Airlines.• Men who have sold their souls to the darkness.• She was accused of being a Salem witch for selling her soul to the devil at the strawberry banks.• Faustus wilfully ends himself; he sells his soul to the devil. 