Paying to attend a baby shower

I'm wondering how other people feel about having to pay to attend someone's baby shower (or kitchen tea or any other party for that matter)?

I've been invited to attend a friend's baby shower that is hosted by her mother and sister. On the invite it states that you need to pay a certain amount which includes only tea/coffee and a slice of cake. The amount is quite a bit more than the typical price for what you get so we are obviously paying for more than just the beverage and cake. I don't even drink tea/coffee so I will just be paying 3x more for a piece of cake and still need to pay extra for what ever I will be drinking instead.

I wouldn't be so against having to pay if they didn't have a set amount and just said we had to pay for whatever we eat/drink ourselves as I would then be able to have whatever I can afford.

I just think it's lousy to invite people to a party and then expect them to pay for the party as well as bring a gift. Or am I being unreasonable?