Internet shopbots compare prices and service levels at competing retailers, creating a laboratory for
analyzing consumer choice. We analyze 20,268 shopbot consumers who select various books from 33
retailers over 69 days for a total of 1,512,856 observed offers. Although each retailer offers a
homogeneous product, we find that brand is an important determinant of consumer choice. Consumers
use brand as a proxy for retailer credibility in non-contractible aspects of the product and service
bundle, such as shipping reliability. Our results also suggest that consumers are sensitive to how total
price is allocated between the item price, shipping price, and tax.