Book excerpt: This dissertation consists of three chapters. The first chapter examines price dispersion in retail gasoline and focuses on differentiation along the service dimension: full service versus self service. Consistent with more intensive search by self-service customers, I find that price dispersion always decreases with the number of nearby self-service stations, but does not decrease with the number of nearby full-service stations. When I segment the market by brand, I observe that the estimates are sensitive to how brands are separated into different types. These findings show that the market is more clearly segmented by service level than by brand type and also highlight the importance of product differentiation when modeling price dispersion. In the second chapter, I examine product positioning and pricing strategies of sellers in a market undergoing a significant restructuring using data from the introduction of self-service technology in the Korean gasoline market in the 2000s. I show that the decision of full-service sellers to exit or switch to self service is positively correlated with the intensity of competition they face. The pricing strategies of sellers differ by product position: self-service sellers compete for price-sensitive consumers, whereas full-service sellers differentiate their product by offering a variety of bundled products and services, such as coffee, carwash or even a nail salon, to compete for less-price-sensitive consumers. Taken together, these patterns have led to an increase in the full-service premium during the market transition. In the third chapter, I study the effect of a government contract on price. Since 2013, Korean government officials have been required to refuel at contracted gasoline stations, at about 5% discounts relative to the posted price. The initial contract terminated in November 2015 and a new group of sellers took over the contract. In this paper, I use this natural experiment to examine the impact of the government contract on gasoline prices, using a difference-in-difference analysis and price data on all gasoline stations in Seoul. I find that, all else equal, posted prices of contracted gasoline stations are about 2% higher than those of non-contracted stations. This finding is consistent with the prediction of models of price discrimination that prices decrease when the elasticity of demand falls. The effect on prices is not uniform across all stations, however. The contract leads to larger increases in full-service stations' posted prices than in self-service stations' prices, and larger increases at stations with fewer nearby competitors. The contract also decreases prices of non-contracted stations very close to contracted stations.