"A wag of the finger to Half Price Books Marketplace. Advertising free shipping for all books on cyber Monday, then marking up the price of the entire stock by the offset amount is not only a poor way to increase activity among the customer base on one's website, but also quite insulting to their intelligence" from a Facebook friend who of course is also getting a PhD in Applied Economics.
He's not the only one with the problem with the store see this discussion.
I think the thing economists often miss is that sometimes people are stupid.
It reminds me of this recent issue with Starbucks charging a $1.50 if you only got 1/2 a pound of beans, but not telling you until the rang you up. The person in this article missed the fact several times he was being charged the $1.50 fee.
I would point the finger at him and call him stupid, but I'm sure that I have missed being over charged from time to time. Interestingly Starbucks was fined for not listing this fee. By making laws that prices must be clearly displayed the government can reduce the cost to the purchaser associated with carefully following prices. I'm not sure it is completely efficient, since enforcing these laws costs money, but I think most people appreciate not having to double check everything is the right price if say you order 3 drinks and 1/2 pound of coffee at Starbucks or get 50 items at the grocery store.