small Smart or vw Lupo? Need tips on how to buy max 1500€

Hello, I am looking for a small, very economical 2nd car for small short trips, I am “forced” to buy a reliable car as soon as possible because I finally got a new job and don’t have more like 1500€ at home. What does the small Smart consume? I rarely drive city rather overland and often. The Lupo 1.0l with 50hp consumes about 5.5-6l in mix operation, I think the Smart should top it or? What should I pay attention to? I read a lot of smarts at mobile dr in stands” engine when starting weak” runs only on 2 cylinders, “motor squints”, engine only half power” What does it have to do with it? I thank you in advance for your answer.