Translation:A taxi from Hamburg to Vienna is expensive.
Is "Ein Taxi aus Hamburg nach Wien ist teuer." correct? This set in the Travel module has created confusion for me. I thought I had a good understanding of "aus" and "nach" being used to express "from" and "to" named cities and countries, while von and zu are used to express "from" and "to" for unnamed cities and countries, buildings, or local sites, etc. I think I have a good handle on how to use "nach" and "zu" but "aus" and "von" both seem to be used to express "from" named cities and countries. Are they interchangeable? Does it make a difference in German which is used for "Ein Taxi aus Hamburg" or "Ein Taxi von Hamburg"?
Yes, there is a difference and in this case they are not interchangeable. The sentence refers to a distance, so you need to use "von ... bis" (from . . . to)
the difference between "von" und "aus":
ein Taxi von Hamburg nach Wien = a Taxi from Hamburg (starting point) to Vienna
ein Taxi aus Hamburg nach Wien = a Taxi from Hamburg (origin of the Taxi :-) to Vienna, which does not make much sense