Amazon will have its “Prime Early Access” sale October 11 and 12. Lots of competitors will be running sales starting today and over the next few days to compete. Most seem to be offering about 20% off on a lot of home automation items, including Meross, TPLink Kasa, Lutron Caseta, Innr, Schlage, etc. I suspect many of these companies want to sell down inventory before releasing packages with the Matter logo.
Everybody seems to have about the same deals and there are a lot of them. Feel free to add anything that looks of particular interest.
Personally, I’m not buying new devices until matter is fully here except for items I would want anyway. I may pick up a few more Lutron switches since they so rarely go on sale. But that’s just a personal decision. 
So far I have seen sales at Wayfair, Walmart, Home Depot, Target, and Best Buy.