If you like to know about your order history you can try this User script (need Tampermonkey plugin in your browser).
Search on greasyfork.org for GOG Orders history prices summary

Sum paid and original prices on orders history pages and get your total saved money on sales.
Add new button (SUM ORDERS on this page) on actual Orders history page in settings.

For sum all your orders on all pages | automatically:
1) go to your account/settings/orders page
2) SUM ALL ORDERS button
3) wait for last page sum

For sum all your orders on all pages | manually:
1) go to your account/settings/orders page
2) SUM THIS Page button
3) go to the next order page
4) repeat 2)

Thank you, this is very useful!

I take it the negative savings are from gifts or something. Also, good grief, my spending is out of control. And that's just my GOG expenses....

Hmm, the negative savings age quite strange.
Can I ask you for a screenshot of your 25th orders history page, please?
Just to check what is going on there.

I need just the right part of the page with the prices.
No order numbers or game names are needed.

Thanks.

Ah, I see what's going on, its because of my cart, which I loaded up with stuff to consider before the sale ends. Here's a shot of the cart and of the last page

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Nice. I threw together something similar a while back for my own curiosity, bit nowhere near as polished as that.

Thanks for sharing.

Thanks. Really the cart items was the problem. I have fixed it.
Update your script for correct numbers, please.

Here's a direct link to it:

GOG Orders history prices summary

New plugin version 1.4:
- you can sum all pages automatically by one button now

I don't know if I really want to thank you for removing the scales from my eyes.
The result hurts...
For all these Euros I could have bought a car - SIGH!

Nevertheless, thanks for another helpful tool.

Excellent script! Very sobering after a big sale.

I do have an issue though. The "PAID" amount includes both when I buy wallet funds and when I spend those funds, which inflates my total spending. Perhaps the script should ignore additions to the wallet, and only track actual game purchases?

Too bad it messes up if you have different currencies in your history, but easily fixable.

Yeh, that is true.
Any idea how to fix it easily, please?

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Thanks. Fixed.
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New plugin version 1.5:
- fix, do not sum wallet funds, only game purchases, now

cool. If you have a reddit account you might share this on r/gog

Thanks, I am glad you like it.
Do not have reddit but if you like, please share it by yourself.