Briefly about manipulation from the book "Psychology of Influence" by Robert Cialdini

Assignment agreement. Method of manipulation: the manipulator puts forward a clearly inflated demand, and then "agrees to a concession", while his goal is just the second demand. You feel the need to agree (based on the reciprocity rule) because you were given a favor and relented. Example: in expensive boutiques, first they set inflated prices, and then they announce discounts.