Lowball technique or Low-ball technique is a strategy in which commitment is gained first to reasonable or desirable terms, which are then made less reasonable or desirable. It is an influence technique based on commitment, in which one first gets a person to comply with a seemingly low-cost request and only later reveals hidden additional costs Lowball technique is getting people to commit themselves to an attractive proposition before its hidden costs are revealed.
Lexicon of Psychology - Terms, Treatments, Biographies,