I started buying at medimops (Germany) a few month ago. I don’t know if they deliver abroad.

https://medimops.de/

eBay and flee markets.

Friend of mine used Videobuster.de for a long time. It has a buy-option too.

I like to buy in FNAC, there are a lot of them, specially if you buy them on their website and later you can pick them on the store.

I know, the world moved to streaming

I did not. I tried (most) streaming services and I decided it was not worth my money (with the full support of my wife).

I buy the DVD, used as much as possible on Ebay or on our own French version of Craiglist: leboncoin, when there is something we want to watch and we don't already have a DVD... that has become kinda rare for the last 15 years or so as there is almost nothing (and nothing on streaming platforms) either my wife and I would be willing to waste our time watching.

And what if we want to watch something and there is no DVD available? Well, there are more than enough excellent movies and series we can already watch on DVD, or rewatch. So, no DVD version? Their loss, not ours.

I don't purchase BR as I don't want to deal with that on my Linux computer (we don't have TV at home, we use a computer ;)