I was told that a Type II costs $60,000-$80,000, while a Type III Costs $120,000-$160,000. I'm not sure those mean much, as each ambulance is outfitted differently, but it gives you a rough idea.
If you have a company in mind of who you'd like to purchase from, or even more than one, contact them and ask for thier base price list and price list of the most comman options. That should get you started and come up with a more realistic price.
I heard our Marquee Type IIs were around 75k, with all LED light packages and possibly everything product that Ferno sells. The AEV units were priced similarly. The bosses choose not to confirm that information, or they just didn't know.