A donation isnt an obligation. If you're willing give then by all means do so, if not then it's not a big deal and if your friend gives you trouble for it then tell her off.

I see your discomfort with her making a GoFundMe the same as you view her not trying to negotiate the price down. When you're comfortable setting boundaries a lot of the discomfort in life goes away and things like trying to negotiate with someone or being uncomfortable with friends looking for (perhaps unnecessary) help on a bill become things you can handle