The two essays explore two topics in marketing - consumer purchase behavior and competitive firm strategies. The first essay examines consumer stockpiling behavior in the retail gasoline market and aims to shed light on what factors affect consumer stockpiling. Past research on consumer stockpiling behavior such as Hendel and Nevo (2006) finds evidence of inter-temporal substitution by consumers that implies stockpiling behavior. However, they do not observe actual inventory or consumption and have to rely on simplifying assumptions about these quantities. I collect a novel data set of gasoline purchase history of consumers with actual inventory and consumption to test several hypotheses that relate consumer stockpiling to price, duration between purchases, and consumption. First, I find that consumers holding more inventory are more price sensitive. Higher inventory increases the impact of price on purchase decisions and those with higher inventory can afford to do more price search before making a purchase. I also find that all else equal, consumers will reduce consumption following a purchase made during high prices; that consumers with lower inventory have a higher probability of purchasing; and that duration from previous purchase is shorter for purchases made during low prices and longer during high prices. The second essay examines competition in a dynamic setting between Wal-Mart and Target in the context of location choices and expansion strategies. Studying this topic sheds light on how an industry evolves and how the market structure is shaped by decisions such as when to enter and exit and where to locate new stores as well as the driving force behind different expansion strategies. One of the early papers by Bresnahan and Reiss (1991) study entry of retail and professional services into isolated markets in a one-shot game. In their model, firms are allowed to enter once and open one store. Collard-Wexler (2014) estimates a model of investment and entry in the ready-mix concrete industry. Again, each firm is assumed to own a single plant in the model. In my paper, I build a structural model in which firms can open multiple stores over a period of time. This setting is closer to reality as competition between firms lasts over many periods with firms making regular entry decisions and often opening multiple stores in the same market. I estimate how entry decisions are affected by competitor's presence and market characteristics and learn about the evolution of market structure and expansion strategies of the firms. The firms are forward-looking and engage in Markov perfect equilibrium (MPE) strategies. The results show that firm profits are affected asymmetrically by the competitor's presence. First, Wal-Mart is the dominant firm with higher profits regardless of Target's presence. On the other hand, Target's profits depend a lot on Wal-Mart's presence. It must have more stores than Wal-Mart (called store advantage) to profit. I also find asymmetry in the expansion strategies of the two firms. Wal-Mart tends to explore new and smaller markets by being the first and often the only firm to enter, while Target tends to focus on major markets with high population and GDP and strives to maintain store advantage over Wal-Mart by matching or outdoing Wal-Mart's decision to open new stores.