Price discrimination is the practice of charging different
prices to different consumers for the same good,
or charging different prices for different amounts bought. First-degree
or perfect price discrimination is the practice of charging
each consumer an amount equal to his willingness-to-pay.
Second-degree price discrimination or nonlinear pricing
is the practice of charging a consumer a price per unit that depends
on the purchase amount. Third-degree price discrimination
is the practice of charging different prices for the same good
to consumers belonging to different groups, depending on the price
elasticity of demand in each group.
International Trade: Balance on Goods and Services Trade