(Biting my tongue & taking a deep breath). No, there are not 'Happy Hours' on the QM2. There is however a 'Cocktail of the Day' shown in the Daily Program. This is a different cocktail available each day at a lower-than-usual price. There are many different bars open during the day and night (including an "English Pub") where you will find the normal prices to be very reasonable and unlikely to be more that you pay at home (a pint of beer is around $4 - approx. £2).
Cash is not used on the QM2 (you can use cash though to buy Casino chips). When you check-in, an on-board account is created for which each passenger is given a card. This is how you pay for your purchases while you are on board.
May I say that this trip is heartily recommended. People often wonder whether it is a mistake to be "cooped-up" for 12 days at sea however, I can personally assure you that there is never a dull moment. There are so many places to visit on the QM2, lectures, activities, bars, restaurants, leisure venues etc., etc., that 12 days can sometimes seem not enough !
Only one thing that I would recommend - it is a shame to cross over to New York without spending a little time there - Generally when there is a public holiday in USA (e.g. Independence Day, Labor Day etc.,) the "return trip" is delayed because the QM2 will often do "mini-cruise" for 4 or 5 days before crossing back over the Atlantic. This is a perfect opportunity to spend a few days in the fantastic City of New York. I believe that this site does in fact offer a "both-ways" Transatlantic Crossing with FREE 5 nights (or so) stay in New York next year - so I really do suggest that if this appeals to you, you should telephone cruise.co.uk/victoria travel and one of their advisor's will give you the full low down.
Whatever your decision, I love the Transatlantic Crossing on the QM2 and I'm sure you will too. Enjoy.
Meant as a truly helpful comment ... if you are looking for happy hours the QM2 is probably not the ship for you and possibly Royal Caribbean or P&O would be a better choice. QM2 is a good choice if you like dressing for dinner, would enjoy two formal nights and appreciate taking your time and a genuine touch of elegance. They have RADA plays, lecturers, string quartets etc and their only concession to the happy hour concept is they have a pub on board. The above advice is not meant to be negative but I am a great believer that cruising is all about matching the right cruise to ones own specific requirements, which are the most important requirements!!.
I have been on 12 P&O cruises and didn't realise that there was such a thing as a 'happy hour' on board their ships. Tell us more Mr/Ms Williams from St Albans!