My most economical yet fun to drive car was a BMW 528e that I got for $1200. It was perfect except the previous driver had smashed the front just enough that the insurance company totaled it. Basically the front bumper was crooked, but the alignment and everything else was fine. I drove back and forth to Rumney at 90 miles an hour for years(seems like cops weren't all over your butt as much back then and almost always just gave me a warning when I did get stopped) , and it got 30 mpg. I think I only had to replace an alternator and maybe a starter and they weren't expensive at all and I was able to easily do it myself.