Markets where number of substitutes exist and one good can be purchased instead of another good.
Below is a diagram to illustrate two substitute products in a supply and demand framework. Beef and pork are both substitutes as most consumers class them as similar goods and very rarely buy both goods at the same time. A fall in the supply of beef creates excess demand and the price of beef rises, leads to a sharp fall in demand . However, because the price of beef is higher consumers to switch to a cheaper substitute (pork) and as a result this forces the demand for pork up as it is a key substitute to beef.
