Contrast - Principle of Influence

When 2 things are presented to you within a short spans of time and both differ greatly in its value.. It is very likely that person is using this principle of contrast to influence you. They will always start high and offer a second lower option, therefore it will create a kind of "illusion" to us that we are getting a good bargain. Also, "deal sweetener" are used to lure people into buying, this is achieved by throwing in of freebies and discounts.

Quoting an example: You just bought a car, which had costed you $60k at a motorcar showroom. After the purchase, the sales person offer you a set of car cleaning kit at only $300 dollars.. you will most likely to take it.