Those four half hour lessons will be the best $60 you could spend as a new player. 30 minutes is plenty - just don't let the time get eaten up in chatter - depending on the instructor, they will be good about using the time efficiently. You are the one paying for that time. If they want to sit there and tell stories or talk about themselves and their experience, tell them to save it and discuss it over lunch some other time (they're buying, by the way). As a beginner, your embouchre will tire after only a few minutes of playing, and a good instructor will not give you too much to absorb and practice in one shot. They should start by getting you the fundamentals - posture and embouchre. If they start by teaching you a bunch of fingerings, then find a new instructor. I won't teach a new student any fingerings aside from B, A, and G until they can hold a steady tone with some acceptable level of quality. I don't bore them to death - I just make sure that the foundation is strong before building the frame.