At least in Germany you get a Smartphone for way less than 100€ and a call + SMS + 4GB data flat for 5€.
If that is luxury what is going to the cinema for 20€ (movie and popcorn) for 2 hours?
I never bought a smartphone for myself, but I've seen 100 EUR smarthpones, and what you get is just a toy (unless you want to do your banking or login to e-mail on a Linux device with severely outdated kernel and no OS updates, which can't go for a few minutes without phoning home, wherever that is)
More expensive ones are not significantly better, either, unless you pick a brand known for keeping up with security updates.
Although I do not live there, I have a SIM card from Italy (Fastweb) which for 6€ lets me have 50GB Internet (of which 6GB could be roaming in the rest of Europe), 100 sms and unlimited calls.
Recently moved and didn't have internet service setup yet. I got an unlimited data bundle from them for £17 for 30 days. Felt like a pretty good deal, and it didn't get throttled at all. Latency was a slight issue with zoom calls though.
You don't get that consistently. You can go to check24.de and get their sim.de offer for 5gb data and sms/telephone flat, but that's a limited time deal. So technically yes, but in general you are more in the 8-10€ ballpark for this kind of offering.
More expensive ones are not significantly better, either, unless you pick a brand known for keeping up with security updates.