November is officially here and that means Black Friday and Cyber Monday — arguably the two biggest shopping days of the holiday season — are right around the corner. Black Friday and Cyber Monday used to be much bigger deals when they were the only time you could lock in major savings on holiday gifts.

The burgeoning phenomenon, which falls on Tuesday, Dec. 3, this year, sees retailers offer special one-day deals and discounts on airline flights, cruises and hotels.

Walmart unveiled its Black Friday plans Monday and said it will start the first of two sales on Veterans Day.Why it matters: The world's largest retailer can have a massive effect on how and when other retailers hold their sales.