The first time I saw this was at Auberge du Soleil in the Napa valley. Although, at $1000 per night, I liked to think of this as 'íncluded' rather than 'free''
. Most of the items in there were high quality local goods too, not national brand candy bars.

I've been at more expensive hotels that didn't give free mini-bars, so the cost of the room isn't always a signal.