Tuscany on $100/day. Possible?

Tuscany is very hilly and rural. Trains and buses are quite a hassle and they don't go everywhere. Having a rental car to get you from town to town is essential.
So, it's not really possible to see Tuscany on $100 a day. $150?--probably.

100 euro for a bedroom in a hotel or for pro person?
For instance you could get an apartment for 150-300 Euros/a day in Florence where you could accomodate 3-6 persons.
in more remote places, you can or course get something cheaper but be sure you are not too far away from village or town centres unless you have a car.

The hotel room is $50 per night. It's a basic room with good reviews, such I found on Booking.com.

As I said, I'll be mostly based in Montepulciano and do walks to nearby towns. So I won't be renting a car this time.

I think you'd have a better chance at $100/day in Florence than in Tuscany. If you can find a cheap pensione for $50-$60/night, leaving you forty or fifty bucks for the day, you can eat quite well in Florence for that. Heck, you can have an espresso and roll in the morning, a beef sandwich at Nerbone at Mercato Centrale for lunch, and a dinner at Ciro & Sons on via Giglio, and still have daily money left for a gelato and some groceries at the Conad Sapori store.

Your budget is very similar to mine. A week doesn't give you much wiggle room, though, so you need to be vigilant. My trips are longer, so I can "splurge" in cities like Venezia, Firenze, and Roma, and stay in lots of smaller, less expensive places to even it out.

I find hotels or B&Bs that serve breakfast included in the room rate, but even if you have to pay for breakfast, it's a couple of euro for a coffee and pastry, a normal breakfast in Italy. I also have a main meal and a very light third meal each day. Grocery stores have lots of prepared foods, so you should be fine. I budget $10 per day for admission to sights and miscellany (coffee stop in the afternoon, gelato, water).

If you check websites of the towns you want to visit, you can get a good idea of how inexpensive most museums are (even in Firenze, the Museo di San Marco is 5 euro or less).

Have a great trip!

Interesting, but I've found that the hotels in Florence tend to be much more expensive.
In Pienza and Montepulciano, you can rent a very nice ensuite for $55-$80 night.

Maybe I should try AirBnB.

Just to be clear, are you talking 100 euros or $100 U.S. dollars (88 euros by today's exchange rate)? And does your hotel rate include breakfast? That would help your food budget.

Backpackers do Europe on shoestring budgets all the time so if your main activity is hiking, I don't know why you couldn't make it stretch. Pack along a reusable water bottle for filling up free (except at taps/fountains marked ""non potabile") and some dry drink-mix packets: they make lukewarm water taste a bit better until you can get to a cold refill. You could also even pack some power bars from home; we do that all the time on our hiking trips as I can get them on sale cheaper here than at stores in remote locations. Eat out of markets or shops with pans of sammies/pizza in the windows. If you drink, get your wine/beer from the markets as well and enjoy them on the terrace of the hotel (if it has one).

Stop into any church that's open: with some exceptions, they're almost always free.

I don't know how much transit that budget will cover so you'll have be a bit careful there, and I'd tuck away an emergency backup fund for the day things might not go according to plan.

I meant 100 USD