What are the economic impacts of holiday and black Friday/cyber Monday? Also when are the best times both price and convenience time to holiday shop?

https://nrf.com/news/the-economics-behind-the-new-norm-of-holiday-shopping

http://marginalrevolution.com/marginalrevolution/2011/11/the-economics-of-black-friday.html

http://www.nytimes.com/2014/12/21/upshot/an-economist-goes-christmas-shopping.html

http://www.nytimes.com/2014/11/27/upshot/dont-believe-the-hype-holiday-sales-wont-make-or-break-the-economy.html?_r=0