D.S.
I have had parties for my kids at the local parks. Jacobson Park is very nice with it's huge playground. August is a hot time of year and you may not want an outside party. Although I always have my son's party in August and it works out great.
Try Lexington Athletic Club's kid's place. That isn't too bad and they do the cake and pizza or hot dogs I think.
Also there's Bounce U. That's on Boston Rd.
I have seen birthday parties at ice cream shops lately! They pretty much have the girls meet there and they let them pick out the ice cream they want and let the kids chat and all that.
Is Chuck E Cheese that expensive? Or Gatti Town? I haven't looked into those.
There is that new party store in Fayette Mall, maybe they help you figure out places for parties too.
Good luck!!