A computer-implemented method for proposing a value to a user includes mapping a plurality of factual cost values for an item type according to amount, each of the factual cost values reflecting an amount that won a bidding process for an item of the item type. The method includes identifying an inflection point in the mapping that represents a first factual cost value. The method includes outputting a proposed value for the bidding process to a user, the proposed value generated using the first factual cost value. The method can be implemented using a computer program product.