interest

added to the balance of the loan, credit card, or bank

paid to the lender

markup

amount added to the price of an item so the seller makes a profit

paid to the seller

markdown

subtracted from the price of an item

benefits the customer

commission

subtracted from the payment the store collects

paid to salesperson

sales tax

add to the price of the item

paid to the government

gratuity

added to the cost of the meal

paid to the server

percent increase

how much a quantity went up

percent decrease

how much a quantity went down