Upvote:3
You do not need any money. Assuming you are travelling from within EU/EFTA, you can take sandwiches, fruit, chocolate, and other food in your hand-luggage, and many airports have water fountains to refill a water bottle (you should check for the terminal you will be at). For entertainment, you can bring books, magazines, e-books, etc.
Food expenses at airports are just a convenience for people who were unwilling or unable to bring their own food. Other expenses are for entertainment, but again you can bring your own. Otherwise, it's a tradeoff between convenience, preparation, and cost. Personally, I rarely spend any money at airports.
Upvote:9
Expect,
My advice would be to pay on the card, unless there is a heavy per-transaction charge, as it will be much more convenient, unlikely to cost much more (and may be cheaper) and will not leave you with small change that you can't use.
Bring reading matter.