A method and system are provided for finding items for grouping items according to sorting characteristics. For example, a price comparison engine is described that obtains the original total purchase price for all items placed in the customer's shopping cart and compares the original total purchase price to further generated total purchase price options to determine if any cost savings can be achieved. Those further total purchase price options are generated by computing the total purchase price resulting from each possible combination of sellers and items in the shopping cart. In some embodiments, heuristics may be used by the price engine to reduce the number of seller combinations and purchase price options generated, limit the price variations upon which the total purchase price options are computed, and/or filter or sort the purchase price options to be displayed.