Is it fair that I am paying hen do costs for those who dropped out?

[Mashedupbanana]

I've been invited to a friend's hen do. Her bridesmaids emailed the dates a couple of months ago and estimation of cost at £150pp but were hoping to bring the cost down.
Around 9 replied to say they would attend, however no one was asked for a deposit and we didn't hear any more about the hen until last week.
The bridesmaids booked accommodation and activities (non refundable) based on the 9 but since emailing to say what is now planned some have now dropped out (with good reasons).
The bridesmaids are now splitting the cost of those who have dropped out between those remaining. This seems reasonable enough but the cost has gone up by a further £100 each.
I had agreed to going based on it being £150 not £250 (and that doesn't include the night out).
As I work part time, in total this hen do will be half my monthly wages :-/
If I could, I would now not go, but I'm sorely aware this would push the price up again for everyone and would be really unfair.
I can't really think of a fair solution to this. If the bridesmaids had asked for a deposit before booking it would have been muh simpler, but its too late for that now. What should happen and what would you do?

Please don't go, I actually feel a bit sick at the thought of you paying half your wages for something like this. Just explain it's too expensive, say sorry and try not to dwell on it. I can't believe the bride would want you to feel like this.

I think you are being very generous in your email OP. I agree with many others that you should drop out entirely.

It is not your fault thatthis event was badly planned, and you shouldn't have to suffer financially for it.

I would say don't go.
When I got hitched I just had a drink at my sisters and then a meal out for hen do.. mainly because 1 of my friends had 200 miles to travel and I thought it was unfair to expect her to pay for more than the Travelodge she was staying in to be able to be there..

..fast forward to her hen do.. she has 2. One was a night out in blackpool I had to travel 200 miles plus had to pay out for meal, bars, VIP area in a nightclub and then was made to feel bad that I hadn't turned up with a gift!! Next is the important one (because I am a bridesmaid I HAD to be there) which is a weekend in center parcs. I have already shelled out £150 for accommodation and I have NO idea how much it costs once you are there (The maid of honour has told me that we are only eating out once thank god) but I do not have a good feeling!! I am the only one of us all with a family (and therefore far less disposable income) but I just didn't feel like I could say no because the other 2 bridesmaids are already annoyed that I can't/won't offer to pay for my dress, shoes and accessories for the wedding (£200 dress, £50 shoes and £50 jacket) :(

Next time I get asked to be a part of someones wedding I think I will have to say no. Its all just far too pricey