The subject invention relates to electronic buying and selling systems and methods. In particular, the invention concerns relations among distinct price curves, price curve attributes (i.e., factors of the offer that can affect the price curves) and buyers or potential buyers. For instance, a price offered to a system user can vary based on total volume of all people aggregating in private environments, cumulative total order by user, ship date, optimal time, as well as terms and conditions associated with the offer (e.g., no cancellation of order, cancellation possible, payment method . . . ).