The problem with the term "tune-up' is that it is an outdated term referring back to when vehicles actually required periodic tuning to keep them running as designed.
But the parts that were either adjusted or replaced ( such as points and condensers in the distributor, the engine timing, carburetor adjustment, etc. ) have either disappeared or are computer controlled and automatically adjusted on modern vehicles.
Although the term still lingers somewhat, it really has no clearly defined meaning today. To most, it just means inspect the vehicle. Some will automatically change the spark plugs, some will replace the filters, etc.
In other words, no one can tell you what it should cost.