I think it will depend on the game (assume you are talking about seeing a game rather than the tour? If not let me know and I will try and find my ticket stub!) One word of advice would be definetly buy them from the club, we bought Benfica tickets to see a game when in Lisbon from a ticket resale website (Viagogo) and had a really bad experience, had to end up buying more tickets at the gate and then struggled to get a refund from Viagogo when they never sent them!
