I work in Italy.
In my office (200-300 people), there are several coffee machines that work either by using coins or by using a pre-credited magnetic key. These machines don't give back the eventual change, so it is pretty common to use magnetic keys to "save" money on that.
A coffee is 0.50€ when paying with cash, but with the key, it is discounted to 0.48€.
I decided not to buy one of those keys because I am a consultant and I'm not sure how long I'll remain working in this office.
Since I entered the office, I saw that this is a practice of my team (5-6) to meet in front of the machine, where someone uses their key to buy a round of coffee (there's usually a good-natured fight to pay for the coffee).
This kind of habit is pretty common with my friends. I do it as well, but maybe in a bar and not in a professional place.
The first day I came to the office, I decided to take the offer of a free coffee, as it is pretty common to offer it to a newcomer in the team. But on other days, I feel awkward taking a free coffee without contributing to the cost.
The coffee machines do not take bills, so I'm also not able to offer the coffee back to others, since as stated I don't have the credit key nor do I carry enough coins.
What should I do? Should I buy a credit key and offer the coffee to other team members in the same way as the others do? Or should I just pay for my own coffee and take my breaks at different times?