You don't have to buy it You can't send it in. You usually have to buy it in the interview room to bring it in. There is no wine! Refuse anything you bring, you can put money into his account and let him buy it in prison. There is a supermarket in the prison, and the price is the same as outside. Physical objects can't be sent in, books can be bought in prison or ordered from prison! Every prison has a library.
You can't send anything in. It's a national prison rule. We can meet from Monday to Friday, but not on holidays! You can only bring your ID card and some documents when you go.