Fascinating April 8 podcast from NPR’s Planet Money. It covers the history and rationale of coupons (dating back to the first coupon deals by Coca Cola and Post cereal), which were created to allow price-discrimination in a post-haggling, price tag world. The discrimination discussion starts around 8 minutes in. Interesting discussion of Groupon as the next, new type of coupon / price discrimination.
(It’s generally legal to engage in price discrimination vis-a-vis end users/customers.)