Offers, such as bids in an advertising network, may be determined and/or managed by accepting an ad budget and at least one ad serving constraint, and then generating offer information using the ad budget and the serving constraint(s). The offer may be generated by obtaining, for each of the ad serving constraint(s), a plurality of points, wherein each point includes a cost per event value and an event quantity value. These points collectively define a landscape. A convex landscape for each of the ad serving constraint(s) is then determined from the landscape(s). One or more points from at least one of the convex landscapes is then used to generate the offer information.