Hi V.,
We love parties at home, but other idea is Deanna Rose, it is free and kids love it!!!! I do suggest though that you check their prices for a hay ride or minning since they love to do that too! You can take the cake there and celebrate in one of their "nests" I think that they charge for these ones, not sure.
Check some info:
http://www.artsandrec-op.org/farmstead/index.html
Some reviews here for b-days:
http://www.insiderpages.com/b/3714792789
In our case, home parties are very expensive, we invite close to 30 kids, they have ablast since they both are in Summer, but just the goodie bags for 30 plus all the props like pinata, water baloons, cakes, treasure hunt, etc, it is usually more than most places.
My daughter also goes to Karate, they charge around $80 for about 25 kids and they provide everything! It is a great cheap way to have an unforgettable party, they even get to cut the cake with a sword! We might do this one next year:)
AKKA Karate USA just beside the main library in 87th street.
Best luck finding a great place!
Mariana