Abstract: In free markets, countless goods may be bought and sold. What was once not traded on markets-for example, access to public parks or sexual and reproductive capacitiesmight be turned into a commodity. Time and again, allowing things to be bought and sold increases both autonomy and welfare. Still, there are pervasive objections to commodification. The first set of objections points to illicit preferences and values and the importance of delegitimating, or not legitimating, those preferences and values (for example, employers cannot "buy" the right to engage in sexual harassment). A second set of objections involves collective action problems: commodification might create such problems (consider the right to vote). A third set of objections invokes equality (as, for example, when people reject the idea that access to public parks should be allocated on the basis of willingness to pay). A fourth set of objections points to information failures and behavioral biases, potentially producing blocked exchanges. A fifth set of objections emphasizes what may be the corrosive effects of commodification on the goods in questions (consider prostitution). These objections sometimes depend on doubtful empirical assumptions, and are frequently overstated. They have different levels of force in different contexts.