I've literally been in this exact boat - except it was actually high school.
One of my group of friends couldn't afford to pay his share for the limo for the y12 formal. So the cost was increased for each the rest of us so we could cover his share, and he still came with us.
We just decided to pay the extra, but my mother was really pissed that I had to pay extra because one person paid nothing! She told me to tell them all to F off and I would just get my parents to drive me.
Obviously I didn't want to follow that advice.. I went with my friends, so I could be with them and also have the full formal experience of riding in the limo. I literally didn't care about a few extra dollars at the time. I mean, I think he was supposed to pay us back, but although he didn't, we weren't worried.
So this kind of thing happens, I guess. People can't afford things, so friends just cover them - if they want to.
But as to the OP who asked the question if she's wrong to not want to pay for transport she didn't take... obviously she's not wrong at all. It was THEIR choice to hire the uber and pay whatever they paid. Just like it was me and my friends' choice to cover our broke friend for his share of the limo - in high school.
But your friends don't get to shove the cost on to you after the fact. That's just not how it works.
I mean, I suppose that all the other 17 friends decided to pay, because they didn't mind. That's fine. Their choice.
But you made a different choice. That's also fine.
But if they've all decided to ditch you and go off to sulk about it... well, that's simply not your problem. You're all adults - except you're the only one actually BEHAVING like an adult!
Just let them go off and behave like over dramatic teenagers do. They are behaving foolishly, but it's not your problem.
You're a grown up with a husband and a life you have to budget for, and you did what you needed to in order to keep costs low for yourself, which is call him for a ride instead of going in the expensive uber. You did the right thing, the responsible and grown up thing.
Just don't worry about their childish temper tantrum. Your conscience is clear no matter what they think.