YANBU
I had an email inviting me to a party a couple of years ago from an ex colleague.
She was celebrating a land mark birthday with her husband, etc,etc. She was planning on holding a huge party on a boat on the Thames, fully catered, all alcohol, etc.
Then imagine my surprise when at the bottom of the email there was a paragraph saying they could not afford the party, the boat or any of it, they would like their guests to pay for for it all, with the £10 deposit each being payable very soon and the remianing £40 each due a few weeks later!!!!!!
I was

Then she went on to say that when she got married she couldn't afford a honeymoon or anythnig so she felt justified in asking.
I wanted to email back to tell her that my 30th birthday was around the corner and that I was doing fuck all becasue I couldn't afford to do anything. I wanted to tell her that I couldn't afford anythnig for my own birthday, let alone hers.
But I thought better of it and simply ignored the email completely.
A few days later I got an email asking me if I got her email about teh boat party and I simply replied and said "yes I did get it" and I left it at that.
A few weeks later I was still being included in the emails chasing people to pay up.
FFS if you want a big an expensive party, F-ing pay for it yourself.
I do think it's rude to plan a party you can't pay for and ask guests to pay for it.