Tune-ups are great for shops because they can define it as anything they
want. Usually a combinations of these

oil change
air filter change
refill fluids
put some gasoline additive into your tank
check engine diagnostic code
inspect tires, brakes, belts
and whatever else that sounds good and not too labor intensive to perform

If you want to save money, give a list of specific stuff you want done. This
will be cheaper than a tuneup.
The inspection and fluid checks often will be done for you whether you pay
for it or not.

Rather than asking me, try asking *them* what
specifically they are "tuning up".

In the old days, a tuneup was a combination
of replacing a few parts that wear out, such
as points, condenser and plugs, and performing
a couple adjustments such as dwell and ignition
timing.

Now theres no points or condenser, plugs go
60-100 thousand miles and there's no adjustments
to be made as the  computer does it all in realtime.

All that's left are the preventative maintenance
items.

Good question.  Ask for a list of services it includes.

--
Todd H.
2001 Legacy Outback Wagon, 2.5L H-4
Chicago, Illinois USA