Why is it necessary for the seller to be able to keep customers from reselling the product in order for price discrimination to occur? There are many products for which you get a discount for purchasing large quantities. For instance, most liquor stores will provide a discount on wine if you purchase a case. Is this price discrimination? If so, what is to keep one customer from purchasing cases of wine and then reselling single bottles at a price above the case price but below the liquor store’s single-bottle price?