Text or phone call. I vote for phone call for something as sensitive as this and especially bc you haven’t seen her in a while so it would be better to get your tone across and less chance of miscommunication.

Tell her that this is a sensitive topic for you (maybe to help her gauge how to approach the convo), you’re really sorry but you can only afford one or none of the trips. Explain to her you wish you could go but truthfully you just aren’t in the best financial situation to spend that much money. And that you hope she understands. You wish she has a great trip and if you feel like, again apologize.

All of my best friends make a lot of money and I’m not financially in the best spot. We’re planning a friend reunion trip, we haven’t seen each other in 5 years. Like you, I can afford a flight but I have to account for food, drinks and possible Ubers. My friend is housing us so that’s a big chunk of money saved. But she suggested in the chat it would be fun to get a lake house on Airbnb. I know my people, so without hesitation I said “I can’t afford that” and she was fine with it. No pushback like “I can find a cheap one, it won’t be that expensive, etc”.

What I’m trying to say is, if someone is a friend, they’d understand. I totally understand the anxiety behind telling her bc money isn’t a fun topic at all and because of her background that she might be blinded about your financial situation. Overall, if she doesn’t take the information well, tbh it’s best to not have someone like that in your life. No one should ever judge or belittle someone’s financial situation, especially if it’s someone who isn’t doing well.

And I’m afraid you might be underestimating how much you’d be spending bc if they’re all wealthy, they might want to go to the most expensive places or spend without any care. Plus it might be hard to handle your finances if the bill is for a bunch of people, they might be people who split the whole bill between everyone.

Either way, best of luck! Just be honest and hope she understands. If she really is your best friend, no matter how many years apart, she will understand. If she doesn’t, sorry to say, she isn’t a good friend. In the end, never sacrifice your finances for a situation like this. It’s not worth you spending your money to prevent the awkwardness of not being able to show up, NOT worth it.

Also idk about your best friend but my best friends would be mortified if they knew I decided to put myself in a worse financial situation because I didn’t want to make anyone feel awkward if I said I can’t come. Hope this gives you better perspective if she were to react negatively. Def hoping for the best bc you deserve it!