I drive a 2000 Pontiac Montana and it has about 92 K Miles on it. What kinds of tune up's should I ahve done? My Dealership told me that there is a $750 package for when the car approaches 100K Miles but I think he may be taking advantage of me what do you think?

That is definitely taking advantage of you, you can perform the tune up yourself and it will cost you a fraction of that price. Did you ask them what is included?

is it a full brake / engine / automotive freshening? do they rotate and balance your tires while a trained 'chair dancer' entertains you?

If not, you're getting ripped off.

They are going to:
Change Transmission Fluid
Change oil and coolant fluid
Inspect Belts & hoses
Tire Rotation
Radiator Power Flush
Fuel Injection Service
Frunt End Allignment
Air Condition and Heating Service

What do you think? The Guy said that it will take a day to do the service :dunno:

Unless they are servicing the A/C because it isn't working, and they are actually removing your fuel injectors and cleaning them out of the vehicle, then it isn't worth $750 IMO. You can do all of those things yourself with a little guidance minus the alignment, which you can usually pay $50 for one at most tire shops.