These charts will show us the the 2015, 2014 and 2013 Black Fridays. There are a lot of things on sale if you buy them with bitcoin. Legend has it that merchants then need to sell a lot of bitcoin that they took in on the sales.
2013 - Price went up through bitcoin black Friday to the all time high, only to sell off violently shortly afterwards.
2014 - Price sold off into black Friday only to bounce and close higher than open
2015 - After 2015 highs of over 500$ the price has found support over 300$ will Friday be a breakout day to the up or downside?
*Bitcoin continues to go up even thought the USD Index is having a big rally, also keep in mind there are more bitcoins on the market than in 2013 and 2014 due to mining.