This dissertation contains essays of the underlying economics of three controversial policies. The first paper addresses the practice of social media platforms of banning users and removing posts to moderate their content. This "speech policing" remains controversial because little is known about its consequences and the costs and benefits for different individuals. I conduct two field experiments on Twitter to examine the effect of moderating hate speech on user behavior and welfare. Randomly reporting posts for violating the rules against hateful conduct increases the likelihood that Twitter removes them. Reporting does not affect the activity on the platform of the posts' authors or their likelihood of reposting hate, but it does increase the activity of those attacked by the posts. These results are consistent with a model in which content moderation is a quality decision for platforms that increases user engagement and hence advertising revenue. The second experiment shows that changing users' perceived content removal does not change their willingness to pause using social media, a measure of consumer surplus. My results imply that content moderation does not necessarily moderate users, but it marginally increases advertising revenue. It can be consistent with both profit- and welfare-maximization if out-of-platform externalities are small. In the second paper, coauthored with Justin Holz and Eduardo Laguna, we study anti-price gouging laws in the US. Thirty-four states prohibit price increases during emergencies and many individuals take costly actions to report violators. We use an experiment to measure the willingness to pay to report sellers who increase prices of personal protective equipment. Over 75% of subjects pay to report even if others are willing to purchase at those prices. The willingness to pay is polarized and increases with price. We argue that reports contain information about a desire to prevent third-party transactions at illegal prices. The mechanism driving reports varies by good: we find a distaste for profits for hand sanitizers but not for face masks. In the third paper, coauthored with Fernando Álvarez, David Argente, and Francesco Lippi (now published in Alvarez et al. (2022)), we study the possibility of banning cash payments in Mexico. We use two quasi-natural experiments that encouraged the use of debit cards and facilitated the use of ATMs in Mexico to estimate the elasticity of crime and informality to the availability of cash as a means of payment. We then construct a simple model to quantify the private costs of restricting cash usage in the economy. Our model captures the degree of substitution between cash and other payment methods at the intensive and extensive margins. We estimate the welfare effects of restricting cash by means of three key inputs: i) the elasticity of substitution between cash and credit, ii) the share of expenditures in cash by type of good obtained from detailed micro data, and iii) the elasticity of crimes to the availability of cash as means of payment. The social benefits of restricting cash usage are driven by the reduction of some criminal activities. The costs arise from the distortions that the anti-cash regulation imposes on the individual choices regarding the means of payment. We find that the private costs of heavily taxing the use of cash in Mexico outweigh the social benefits that we identify.