You are welcome to purchase wine during the trip. Please ask the instructor if there is enough time at the end of the visit for you to make your purchase without impeding the progress of the trip. However, not all estates sell at the estate; in Bordeaux, for example, very few of the Classified Growth chateaux sell wine at the chateau (they sell exclusively through wine merchants).
We recommend that you ask your government’s customs office for their rules and regulations if you intend to bring wine back into your country, or have wine shipped to you.
In any case, you always have the option of bringing wine home with you in your checked luggage. You may have to pay some amount of duty on your wine when you go through customs; please check with your local authorities for further information.