The opportunity cost of $30 for new clothes can be $30 worth of food or also $30 worth of books.
Explanation:
An opportunity cost is anything that costs you for buying something else with the money that you had which you could use to buy something other than what you bought.
Hence, if you buy $30 worth of clothes, you miss on buying $30 worth of something else as you used the $30 that you had on buying clothes.
