The antonyms for the phrase "makes a buy" could include "sells," "returns," "gives away," or "returns to store." When someone sells something, they are giving it up rather than acquiring it. Returning a product suggests that someone did not want to keep it, and giving something away means it was not acquired with the intention to keep it. Returning to the store could also mean that the acquisition was unsuccessful or not satisfactory. These opposite actions to "making a buy" all suggest different reasons for not wanting to keep or continue with a product, whether that be for financial, personal preference, or quality reasons.