Used cars up to 3000€ for beginners

Hello dear people, I’m driving my driver’s license and I’m going to buy a car (I can smell the freedom when I’m thinking about driving my own car). I don’t want to or can’t spend more than 3000 euros. Now an acquaintance has recommended me either to look for an Opel or a Peugeot (206). I live in a big city (Vienna), so I’m going to drive there mainly. I also want to take the car on vacation (including holidays). I think I’m going to drive, drive, drive as much as possible. That’s why the car should consume as little as possible (so most likely a diesel?) It will be in the underground garage with me if that’s any decisive factor when buying a car. I will also mostly drive the car alone, have no children or dogs, so the smaller the better (as long as it’s not a cube car) I try to list what’s important to me. : – Cost-effective consumption – Removable rear bench (also wants to be able to transport things again and again, e.g.Ikea) – optics (Peugeot would be nice, Opel would be less…) I really have no idea about cars, so the simpler your answers are written the better! lg from Vienna, Daniel