A market is a situation where there are buyers interested in purchasing a product and sellers interested in selling a product. It is generally described geographically, as in, the US gasoline market, but it could also describe a more localized situation. On the buyer side (often called demand), the number and characteristics of the consumers are important. Marketers need to understand what products consumers are or might be interested in purchasing. It is also important to think about the ways those customers want to make the purchases, such as over the internet, door to door, or at a brick and mortar store. Other factors like income, how often they make the purchase and the prices of other products are important to think about when considering consumer demand. On the supply side, the number and characteristics of sellers are important to consider. Marketers might look at the market share of a specific firm in a market, which is the percent of the total sales made by a specific firm. For example, a marketer might consider what is the market share of Exxon in the Arizona gasoline market when considering expansion or promotional ideas.