I live on the Upper East Side in Manhattan. I walked by a children's clothing store this afternoon and did a double take when I saw a sign in their window: "Birthday parties starting at $400". By equal measures intrigued and appalled, I walked in and asked for information. Party includes: 1 birthday girl plus 9 guests, pizza and juice boxes, 1 party favor per guest. Girls get makeovers, nails with glitter polish, glitter tattoos. Additional guests $30/child. Add a theme (fashion show, American girl, etc): $200.
Pretty sure I could do the same thing for, oh, $30, max, in Manhattan.