Here's my response to another similar thread on the Family board.
We just had my DD's 7th birthday at BAB. We spent $150 (6 kids total, each one got to spend $30--two of those kids were mine). When I booked online, they gave me a "deal" if I increased my $25 amount per child to $30; then the birthday kid was free. I'm sure you could do less, but this let the kids dress them and with so few children, it wasn't a big deal.
We had cupcakes/juice in the food court 1/2 an hour before the party, walked down and they built their bears. It was very cute and everyone loved it I think. My daughter got an extra bear that everyone signed, a sash, and a photo with everyone.
I also got back $30 in BAB bucks, probably $20 of those were from the party alone (but not positive). Honestly, I thought it was a fairly reasonable party, considering everyone got to keep a bear. And it was fun! Just doing cupcakes/juice alone saved a good amount.
So, if I were you, invite just a couple kids (you need six to be a party) and hopefully they can come. My guests drove about 20 minutes.