A flash sale is a generally short period of time promotion. It is an exciting way to create hype and boost sale before the actual Black Friday and Cyber Monday. It can be few hours before the expected event or a day or two is also a good idea.

A flash sale testing conducted saw a 51% growth in traffic, 50% rise in conversion rate and a whopping 236% increase in revenue. Flash sales can be tricky so you need to carefully set your limitations and conditions before considering to use this approach.