The Rift S tends to come in stock from Oculus every Tuesday as far as I remember, but you'll need to be quick to buy one because they sell out pretty quickly.
Best Buy in the States also get new stock in every now and then I think. Best bet is to check for that regularly in the Oculus subreddit.
Yeah, they'd been out of stock for a while due to the pandemic and holiday rush. But I recently got an email saying the Rift S was back in stock. By recently I mean two days ago. I was too impatient to get a VR headset, and paid a scalper way too much for my Quest. I mean, I paid $799 plus tax, when it should have cost 499 plus tax. But hey, I got my Quest, and Trump paid for it. So I can't complain too much. Still, if I'd waited I could have gotten one for actual market value.
Just be patient and keep an eye out.
Lo, a quest! I seek the threads of my future in the seeds of the past.