A reasonable price range for a FTD3/LevelB sim is $5-8 million. The exact price will have a large dependence on the amount of "stimulated" versus "simulated" equipment and the source for the validation data. For most complex twin engined aircraft, the aircraft type does not have a big impact on sim price.
Going to an aircraft manufacturer like Agusta or Eurocopter for the validation data is likely to raise the price of the sim by ~$1 million. If possible, you're better off supplying an aircraft to the sim manufacturer for flight testing. You'll end up with better quality data tailored exactly to your aircraft and how you want to train, and you'll retain the rights to the data so you can build a 2nd sim if needed at an even lower cost.
Depending on the size of the motion base you choose (36in - 60in) the price can fluctuate by several hundred thousand $. Visual system projector count/selection will also impact the price, but those costs are smaller.
You'll then have the costs associated with spares, employing a sim tech, paying for the certification process (does not apply in the US), etc. I don't have an estimate for these costs other than saying that the UK CAA charges 16k pounds for certifying the sim.
Most people don't realize it, but owning a sim is a big deal. Fortunately, they pay for themselves in short order in terms of improved safety, reduced aircraft operating costs, and additional revenue obtained by selling time on the sim when you are not using it.