In Tuscany, as in most of the wine growing regions in Italy, most of the wineries are small and family run.
So, you should expect to pay for visiting it and tasting wine and the snacks they provide. The fees range from $10 to $60.
The wineries usually require appointments.
For locating the wineries offering these services, you can also have a look to these guides detailing wineries in two of the most-known wine-growing areas: Chianti and Montalcino.