Best way to visit Mont-St-Michel?

Option 1- $500 per person- I would skip this one. It seems beyond expensive.
Option 2- $100 per person- Well this is better, but you will probably be arriving right at the peak crowd times.
Option 3- $? Rent a car for the day and drive there as early as possible, park in the lot, take the shuttle, spend as much time as you want and then return the car.

I'll take option 3 every time. Except, I would definitely add a night on MSM itself. Those that say staying off-island is just as good or better, I'll bet have never actually stayed a night on the island. I have done both and there is no comparison. Also, any "day trip" will dump you there in the middle of the day, and in the middle of the crush of tourists dropped off by the busload.

Yeah -- I live less than an hour's drive from Mont-Saint-Michel and my recommendation would be to arrive late in the day, check into a previously-reserved room, have dinner (you might consider the new restaurant that is much better than the standard ones on the rock) and enjoy the solitude of the place in the evening and the early morning (force yourself to get up early and walk the ramparts in near-total solitude).
Years from now, you'll remember it.

We are desperately wanted to visit MSM but the logistics sound tricky for a first time visitor to Paris. We do NOT want to drive from Paris to Bayeux but I am concerned if we take a bus, then the shuttle, we will be arriving at peak crowd times. An overnight at MSM is not an option as we have already booked a hotel in Paris. If we get up really early, is it possible to beat the rush, enjoy the sunset and dinner and then head back to the city?

anessa, The price is ridiculous for option 1 ($1000.00 per couple!)
Neither of the tours sound like a good deal money-wise. You can rent a car for much less than $200 (if you are two) and have more than 3 hours there, even if you drive back to Bayeux the same day.
I hope you find a good choice for you.

Oops, I confused my response to anessa with the query by the OP. IMO, any attempt to do MSM in one day from Paris is possible, but doesn't sound enjoyable. Getting an early start is smart, but first figure out your train and shuttle or bus times, to make sure all will work out. You will still be there when it is crowded, but I have been when it is pretty crowded, and still enjoyed the Abbey and the view from and of the Mont. Check all your transit details, and it may be possible.

Thanks all. We will be staying in Bayeux with a rental car. Overnight stay on M-S-M sounds like the way to go.

Yes, definitely.