And that's okay. Everybody is allowed their own little luxury; the thing is, if you can't afford it, you shouldn't try to drag everyone around you to help you get it.
Moving together is the fastest (and most extreme) way to get to know someone deeply. I've lived in many cities, with many different people, and with all of them I had transformative experiences that completely changed my mind about them.
People who seemed really put together were actually really messy inside the house, or people whom I was best friends with turned out to have huge, hidden parts of their personality I didn't like at all and had never seen. There are things you only learn when you cohabitate the same space.
In this story, the roommate basically wanted to coerce her friend into paying for the coffee machine by giving her no other option to make herself coffee, but that's obviously unfair. There is no question about it.
If I were her, I simply wouldn't use it and, of course, wouldn't pay for it, even if that means not drinking coffee or buying myself a cheaper coffee machine. Of course, I would try to talk to my roommate, but seeing how she handled things is definitely enough for me.
And I even think OP should keep an eye on that, especially on the entitlement the roommate displays by thinking she can decide whatever without asking and that the rest must follow along.
Maybe she felt her roomie said yes telepathically? Hey! We might be ignoring that she might have had special powers. She knows that in the near future, her roommate will be really interested in owning an espresso machine.