I find it odd that you were never officially asked to be in the bridal party, and you were never included in any of the planning thus far. I have also never had to contribute towards the cost of the shower, and I do not know anyone in my friends/family circle that have had to either. I have contributed favors, invites, decor, games, prizes etc for various events, though.

I personally would be offended if I was asked to do all of this, because that is alot of money to ask for, especially when there was no discussion about what everyone was comfortable spending in the first place!