Bridesmaid bullshit


I am a bridesmaid in a friends wedding (we aren’t very close). She is picking out bridesmaid dresses that are $200! I’m a stay at home mom and live in a small Apartment. We have just enough money to pay our bills and some to start saving for our wedding which will be just a month after hers. I only paid $350 for my wedding dress, and I just don’t have the extra $200 for a bridesmaid dress I won’t ever wear again. How do I tell her that I can’t afford the dress?