Gasoline or diesel

My name is Fabian, I’m from the Stuttgart area and I’m 29 years old. Now to my own question. I’d like to buy a new used car. Keep an eye on VW Passat Variant. Now the question bothers me: petrol or diesel. Since the two are almost the same price I have to look at the other costs. However, many of my friends say that a diesel is not worth it with me, because I drive too little (about 12000-15000) and a diesel in The purchase is expensive. I can’t make it clear to them that the prices used are almost identical. I get only the answer from them, a diesel is only worth 20000. Insurance and tax are a bit expensive, but diesel is cheaper and the choice of diesel vehicles is much bigger. What do the experts here in the round say to my thoughts?