Because Walmart likes to release its most jaw-dropping TV deals as a handful of pre-meditated doorbusters, more shoppers will be waiting in the wings for the clock to strike a certain time (rather than calmly perusing several pages of TV deals) — which means TVs selling out is more likely and time is of the essence.

When it comes to Black Friday, Amazon is taking center stage. The retail giant just announced its official Black Friday sale will begin on November 21 and run through December 2. From Dyson and Levi's to Hot Wheels and Ninja, you can expect tons of massive markdowns on your favorite name brands.