You can buy an electronic game for $25 at the Campus Store or for $15 at a nearby shopping mall. You can buy a computer for $1000 at the Campus Store or for $990 at the nearby mall. Should your "where to buy" decision be the same or different in the two cases?

• The same because the marginal costs and marginal benefits are the same in each case.
• The same because the opportunity cost of buying at the Campus Store is zero. Different because buying the game at the shopping mall provides a greater percentage discount.
• Different because the computer is a higher surplus item.