A family member of mine in Germany is looking for a laptop in the 100-200€ price range. It would be okay to buy used and it shouldn’t be one of those modern Celeron laptops. It should still have a fairly slim design and a processor at least good enough to run Minecraft at low settings with ~30fps on Linux. Is this even a thing, and where would be the best place to start looking?
Absolutely not. The carbon is already very slim. It really sounds like they want a MacBook which we both know is not gonna happen for 200. Your relative needs to come to grips with the reality of their budget or just keep saving. Best time to buy is after Christmas when people get new shit and sell their old stuff.