Hi there,
i'm currently working for TCX and i could inform you about prices onboard.
Mixers= 0.70
Miniatures (gin, vodka, whisky... except baileys)= 2.80
Beer= 2.5
REmeber, headsets are not free. So, if you dont want to spend 2.75, you better take your own headsets with you. They'll work onboard.... but if you want them to work in stereo, you'll have to purchase 1 adaptor which costs you £1.
I'm not operating on the 330 yet, that's why i cant really tell you where to find a good seat. ah, screens are in every single seat; very personalised.
enjoy your trip!