Which graphic card for around 100 euros ?

Bouquins You can probably pick up a good GTX 1060 3gb for around 100-150 euros. It's not the best card out there, but it's still relevant today and is pretty awesome still. I'd skip the GTX 1050 or GTX 1650 cards.

you might be able to get something from the radeon rx 5000 series for around that price? id advice to get away from nvidia if you want something that works out of the box

Bouquins

looking for a graphic card which work out of the box with Solus Budgie

You want AMD.

Lucien_Lachance my experience was that the 5500 series wasn't as good or performant as the RX580. I don't know if you could pick up a 580 for less than 150, but it's not a bad card today still.

Brucehankins i was very happy with the 5700xt, but it looks like its more 200 euros

Brucehankins
Since Bouquins has been using a 560 Ti, I am guessing graphically heavy tasks aren't in it. For that reason, and the idea of keeping a card for so long, I would say that having a card two generations newer was probably the better choice if the price is close. For tasks even a 560 Ti could do, even a 4GB card should be good for a while yet also. Unless you mean that the RX 5500XT has issues in Linux (I haven't owned one)?

Teggs it didn't have any issues I can remember, but the performance on games wasn't as good as the 580 (judging solely by FPS on highest settings for the games I played and my hardware setup). But yeah, given the tasks they're probably doing, if you can find a 5500 or 5600 on sale, it would be worth it.
I'd still try and avoid the entire Nvidia 16 series as those cards were mostly hot garbage. If you really want Nvidia and gaming or graphical performance isn't so much of an issue as support.....I guess a 1650 or 1660 is okay.