consumer equilibrium  the point at which the marginal utilities per dollar of expenditure on the last unit of each good purchased are equal
consumer surplus  the difference between what the consumer is willing to pay for a unit of a good and the price that the consumer actually has to pay
diminishing marginal utility  the principle that the more of a good that one obtains in a specific period of time, the less is the additional utility yielded by each additional unit of that good
disutility  dissatisfaction
equimarginal principle or consumer equilibrium  to maximize utility, consumers must allocate their scarce incomes among goods so as to equate the marginal utilities per dollar of expenditure on the last unit of each good purchased
marginal utility  the extra utility derived from consuming one more unit of a good or service
substitution effect  the tendency of people to purchase less expensive goods that serve the same purpose as a good whose price has risen
total utility  a measure of the total satisfaction derived from consuming a quantity of some good or service
utility  a measure of the satisfaction received from possessing or consuming goods and services