If you plan to visit wineries in the Chianti area and eventually have wine tastings by spending a day or two, I suggest you consider a wine tour which will maximize your visit.
Firstly, you could find it a bit complicated visiting wineries in Italy: not all have tasting rooms and most are by appointment only. Secondly, you need a car; think most of non-italians hate driving in Italy…….
A one-day wine tour including visits to 4/5 wineries would cost around 100 Euro per person, and generally a full lunch and tastings are included.
However, should you tailor a your own tour, have a look to the following websites of wineries located in the area.