A2: Random
The Rothbunch blog describes how they approached replacing their sidewalks (as ordered by the city of Ann Arbor), explaining how they got a low bid from a company that had an angle: “They admitted that they gave me a better price because we are the first house in our development and they wanted the chance to get more business in our neighborhood. It worked out for both of us….I got a real good price (and a nice job) and they were able to get several other jobs in the neighborhood.” [Source]