1. A non-transitory computer-readable medium embodying a program executable in a computing device, the program comprising: code that provides item classification data that associates each of a plurality of item classifications with a corresponding set of attributes from a plurality of sets of attributes; code that obtains a selection by a user of one of the item classifications from a client; code that generates a first user interface that includes a listing of the set of attributes corresponding to the one of the item classifications according to the selection, the first user interface being configured to obtain at least one input value for the set of attributes from the user; code that sends data including the first user interface to the client; code that obtains the at least one input value specified by the user for the set of attributes from the client; code that determines a suggested price range from a set of historical sale prices in an electronic commerce system for a plurality of items that are classified under the one of the item classifications and match the at least one input value for the set of attributes; code that generates a second user interface including the suggested price range; and code that sends data including the second user interface to the client.