  We study large markets with a single seller which can produce many types of
goods, and many multi-minded buyers. The seller chooses posted prices for its
many items, and the buyers purchase bundles to maximize their utility. For this
setting, we consider the following questions: What fraction of the optimum
social welfare does a revenue maximizing solution achieve? Are there pricing
mechanisms which achieve both good revenue and good welfare simultaneously? To
address these questions, we give efficient pricing schemes which are guaranteed
to result in both good revenue and welfare, as long as the buyer valuations for
the goods they desire have a nice (although reasonable) structure, e.g., that
the aggregate buyer demand has a monotone hazard rate or is not too convex. We
also show that our pricing schemes have implications for any pricing which
achieves high revenue: specifically that even if the seller cares only about
revenue, they can still ensure that their prices result in good social welfare
without sacrificing profit. Our results holds for general multi-minded buyers
in large markets; we also provide improved guarantees for the important special
case of unit-demand buyers.
