How would you have handled this?

A few days ago, I called my niece Janice to chat.  While on the phone, she asked, "You aren't on Facebook, are you?"  I told her no, and she went on to extend an invitation to me that she had originally posted on Facebook to other friends and family members to attend her 30th birthday party that was being held at a painting studio in which guests would create their own painting under the instruction of an art teacher.  I said, "Great.  Send the details to me via email."  She wrote to me and included the date, the time, and the name of the studio.  I responded that I would definitely be there.

Later on that day, I was corresponding with another niece Katie (not Janice's sister) and told her I was really looking forward to Janice's birthday party.  Katie wrote back and said she was excited, too, and suggested we go together and that she wanted to pay for me.  I didn't really understand right away what she meant by "pay," but I subsequently found out from another family member (huge family) that when Janice posted the invite on Facebook, she also posted that each person had to pay to attend.   I never found out exactly how much, but it's somewhere in the range of $35-$45.  This includes all the art materials, the art instruction, and beverages.  The studio does not provide food.  I was told that Janice did emphasize on the Facebook post that she did not want any presents and wanted only to enjoy the company of her family and friends for her birthday.  By the way, Katie probably offered to pay for me because I often go over to her house and take care of her dog when she is away, and even though she always offers to pay me, I always refuse because she's my family, and I do it because I love her.  

Like a lot of people who currently work in this industry, my income is below the max poverty line.  I cannot afford to pay my bills as it is, so there is certainly no extra for entertainment.  When I initially spoke to Janice on the phone and then received her email invite, I was relieved and happy that I would actually be able to go because I had a gift to give her.  Recently, I was given a gift card for WalMart, but due to ethical issues I have with that retailer, I knew I would not be using it.  I thought of giving it to someone who actually shops there, rather than tossing it, because I would hate to have WalMart make a profit like that without having to give up any inventory.  Had I not had the gift card in mind to give to Janice as a birthday gift, I would have declined the invitation.  

First off, I have never heard of someone throwing themselves a birthday party and asking their guests to essentially pay for it.  I find it a little disturbing.  Secondly, the fact that Janice, in her Facebook post, seemed to be reminding everyone that she did not want any presents, but looked forward to only the warmth of her loved ones seems a little disingenuous when she is not paying for the party.

I thank God that I found out about this ahead of time because I could have shown up without any money and been refused entry.  My siblings are aware of my financial situation, and I am okay with that.  My many nieces and nephews, however, are not privy to that information, and I don't want to share it with them.  They are not my contemporaries.  Since I both spoke on the phone to Janice AND received info via email, I cannot understand why that little bit of information was left out.  Maybe it slipped her mind, maybe she's embarrassed, etc.

Anyway, I wrote to her the next day and mentioned that another niece had said something about 'paying??'  She has not written back to me yet.  I know I will not be attending because I simply do not have the money, but I feel like none of this would have happened if I'd had all the facts when the invitation was extended.

Am I just old-fashioned thinking it's odd that someone is throwing themselves a party and asking others to pay for it?  I don't think it would be unusual to suggest a non-occasion get-together like this one (painting party) where everyone pays for themselves.  I'm also bothered that she was not up front with me about the money.

Any thoughts?