Price of related goods:
a) Substitute goods – Whenever the price of substitute goods raises they become dearer whenever the price replaces goods falls they become cheaper. Whenever the price of one good increases the consumer will replace the other good.
b) Complimentary goods – Whenever the price of complimentary goods falls, all along with the increase in its demand. The demand for complimentary goods will also rise. In case of complimentary goods price of one good and quantity demanded for another good are inversely related.