Last May, I was in a similar situation. My daughter was having a birthday and I was 2 months away from having my baby boy. I decided to have my daughter's party at the park. I found a great park that was covered. She loves butterflies so I found butterfly wings on e-bay pretty cheap and bought about a dozen of them. I found some pirate hooks and patches for the boys at the dollar store. It was at a park, so the price was cheaper than at any other place in town I could think of having it (other than home) and the girls loved their wings. They spent most of the time running around and enjoying the day. We also had a butterfly pinata and I bought all the supplies and decorations at the dollar store. Depending on what her favorite barbi is, wings could work. Or, you could have the girls bring their favorite barbies. Maybe for party favors you could find dresses for them at a local dollar store or discount store. I've also seen kids decorating boxes for their barbies with gems and stickers. Again, everything was found at the dollar store. It should be easy to find anything in barbie you could want for a reasonable price.