I'm actually planning a build a bear party for my little man who will be 4 on May 2, 2012! I looked at the pricing, and it depends on animal choices you select. I decided to go with the 10 - 15 dollar range (it gives them approx. 6 animals to choose from, and at that age, they don't need many choices). Our build a bear is in the mall, so after they build their bears, we are going to go to the food court for cake (cupcakes) and ice cream (single serving cups) and a ride on the carousel.
Edited to add - I have done a party at home for his first birthday, Chuck E Cheese for his second, and Monkey Joes (a bounce house type place) for his third.
We don't do outside parties because the weather is so unpredictable - I have had it SNOW on my birthday (May 20th), and for my little guys second birthday, all of middle TN was flooded!! (Google TN may 2 2010 flood!)
This one seems to be the least expensive so far!