I've just recently finished my foundation year, but it really depends. You'll have to catch the early train for Carmel if you have 9ams, which is about 3 a week for me. Considering it's not off-peak times either, the train will cost quite a bit. When I took it at the beginning of the year I spent around £20 each week. It's a ~25 min journey and the walk from the station to Carmel is about 15-20 mins, which is why I went for the bus instead. I live in halls (Melville), and the bus stop was around 15 minutes away from me. The bus does take a long time though, around 45 minutes, and it is cheaper than getting the train, at least for me. You'll have to get the 10 bus as it drops you right outside of Carmel, not the 10a, since that'll drop you off a bit away from Carmel and it's a walk.