The real sales happened 3-5 weeks ago. Prices are actually up since then.
In my experience the actual sales are in January to mid-February.
Sometimes there are random decent 'sales' around black Friday/cyber Monday. Those are usually targeted towards people shopping for Christmas presents, so there's really only a few good deals.
Then the prices skyrocket for Christmas because everyone that waited until last minute to get Christmas presents will be price gouged.
Finally, in January - mid-February, they actually get rid of old stock. This is a great time to buy things where there's a newer model, usually things like laptops and RAM kits.
Main difference these days IMO is that you just don't buy stuff around Christmas online unless you need it, especially technology stuff. They price gouge it like gas in the summer.