Do you know where I can buy?

We want to get pictures taken for Halloween for my daughter and also get her 7 month pictures done. We would like to buy a cute dress for her to wear but I can't seem to find one. I've been searching ebay but don't really know what to look for. I'm all about tutu dresses and stuff for photos. This will be my daughters first professional pictures and I just want them to be perfect. Any ideas? Nothing too expensive please!