The model s is 100k bucks. That's why I'm not buying one.
Original price of our Tesla Model S 85 was $94K before taxes and incentives, so about $97K all in. So your estimate of $100K is in the right ball park.
We didn't buy new. We bought our Tesla second hand through the Tesla "CPO" program. For a two year old car with almost 60000 km, Tesla gave us a major discount off new, and included new tires, brakes and charging cord.
Over 8 years, we'll save $10K in fuel. We kept our previous 4 cars (prior to the MB) to 12 years and >150000 km each, so we are comfortable with long term ownership.
With that savings included, we'll spend $30K more than simply driving the Mercedes into the ground over that period. It was pretty easy to make that decision.