I remember a few years someone mentioned how by using a specific URL I could clear the cache of the website on my web browser. I can't remember it and all I can find now when I search is annoying instructions for the galaxy client.

Any help?

My main issue is that since today GOG decided to only show me prices in US Dollars.

Is "Currency" at the bottom of the page set to EUR? If not change it.

Have you tried to change the currency at the bottom of every page?

Edit: maybe this helps, too: https://www.gog.com/user/refresh

Edit 2: and just in case...

How to clear cache and cookies:
So, how to clear browser cache?
Using Internet Explorer, Edge, Google Chrome, or Mozilla Firefox, you can quickly clear your cache with a keyboard shortcut.
While using your browser, press Ctrl+Shift+Delete simultaneously on the keyboard to open the appropriate window.
Remember to close the browser and restart it after clearing the cache and cookies.

For the currency, clearing the cache is one troubleshooting method, but here is also another one if it doesn't work
https://support.gog.com/hc/en-us/articles/360011546833-Wrong-prices-and-currencies-on-the-website?product=gog
"To resolve problems with wrong currencies being displayed, or your local previously supported currency disappearing from the available list of currencies, try proceeding to checkout with any game in your basket. Exiting the checkout screen should afterwards resolve the issue."

I tried this before and now, nothing. As I replied to the others (see attached screenshot), I no longer have the option to change it. The refresh was what I was looking for, but unfortunately did nothing. About clearing the cache, I don't want to clear/delete everything from all sites. Everything else works fine. Is there a way to just clear the GOG ones on Opera?

You're not using any VPN or something like that by chance? Maybe you forgot to disconnect? Going to checkout normally always worked.

No VPN.

Maybe a hard refresh (Ctrl+F5 for Opera)? Alternatively, you could try looking for the page's cookies in the settings page.

Hard refersh didn't do anything to fix it.

I have no idea how to search for cookies in settings, BUT, if I go to my account settings where I can set my location among other things, I don't have the option to change the currency even there. It's so weird.

The question was two parted.
You only denied the first part.
What about the second part?
Some other third party program in use?

...Seriously now?

Ok. No to both. I don't even know what "something like that" could be.

Yes...seriously!

Because, if you encounter an error, that the vast majority of other users don't encounter, the chances are pretty high, that something on your side is causing that error.

And since many people here use third party programs to "customize" their experience with GOG, it's definitely not too far out an idea, to ask, whether you do the same.

And since many GOG users probably use USD as their default currency, they won't even notice, if other choices are missing for them - even if they encounter the same issue as you, due to the same third party program (only for them, it is no issue, because: USD = default currency).

Have a nice one.

Edit: worded the last paragraph more clearly

Well as I said, hopefully clearly enough, I don't use a VPN, or anything to do with any altering of my online situation.

I don't know if it is coincidence or not, but this seems to have done the trick.
Thank you for your help.

Also thank you to all who participated.