Invitation - financial embaressment

We've been landed in same boat! #1ds getting hitched for 2nd time no less and "do" is to be in a huge country venue in middle of peak District, a hefty 90miles away for us in Lancashire , and other close guests are staying at venue but rooms were £230!!!!(yikes) plus all the other expense althought they're expecting a baby now so pressie will ot be happening! We are a bit miffed that they're doing the big showy-offy wedding second time? I know it's the bride's first but why not a classy do and a scaled down reception? We could afford it but have mad arrangements to stay in country pun/hotel a few miles away and will be combining with a 2day stay so we can visit Chatsworth too! It is an insensitive way of behaving on part of the couple who are loaded and no spring chickens!

The friend with a significant birthday has simply asked you to her party. In planning a guest list, she presumably chose those people she would be happy to attend her party and are close to her.
If you had not been asked, you may well have been upset or offended . I am sure she would not sit with a list of friends in front of her thinking ‘oh I won’t ask her she can’t afford it’.
An invitation is not compulsory. I really don’t see what’s wrong with you saying something along the lines of “sounds lovely, but with the way things are at the moment I won’t be able to make it”.
Everyone has budgets - no big deal.

.....and ys, honesty is best policy but you can dress it up a bit! Maybe saying that you'd love to attend however you're unsure about the trains situ? /Moneysitu?/anything else that's frankly the truth, trains may be dodgy by then with strikes etc and everyone's having to wait with baited breath about the colossal bills expected so she should have full empathy.send her a good gift and card.a friend will understand.

Hithere

"Thank you for the invite, I am not able to attend"

She's a close friend. That response would be very hurtful.

OP I agree with others, just explain. She may just want you to know you're invited, but with no real expectation that you will go to that trouble and expense.

Have you looked at coach travel which is much cheaper than the train? And Airbnb is cheaper than a hotel.

I agree with SuzieHi. Just say you are unable to attend but want to wish her a lovely day. Her finances may be in a better state than yours so you could invite her to stay for a few days if she is ever your way ?

Another good reason not to go …. Unless you know and like a lot of other people there it will probably be a very lonely trip. You will have time before and after the party and your friend wil be spending time with other guests.

My suggestion on reply ..

“Thanks for the invite, unfortunately I can’t make it but I’ll be thinking a of you, have a brilliant time”

i think it would have been far worse if your friend had made the judgement that you would be unable to attend and so had left her off the invitation. When I invite people to a celebration which will cost them money because they will need to stay in a hotel or B&B I encourage them to make it part of a holiday in the district and an opportunity to see relatives and friends. All I can offer is space for camping.

I think sweeties suggested response is a good one

“Thanks for the invite, unfortunately I can’t make it but I’ll be thinking a of you, have a brilliant time”
But you might preface it with 'Thank you for including me in your inviation to your party, but unfortuanely etc.

Then you can sent a present/flowers to your friend for the day.

You should be pleased that your friend thought to include you.

All the best.