Everyone wants gratification. They might not know what they themselves really want, but they will realize they have a good deal when they feel satisfied. So the vendors need to think very hard about what make people tick.
Make customers an offer too attractive to refuse.And when they swallow that bait, the gratification by great value for money, though invisible yet more additive than any drug on earth, will drive them back again and again for no other vendors can satisfy them anymore.