We have huge families. First birthday party's are similar to wedding party's (although there were 500 at our wedding so no where near as big as that) where it's a big hall with food and alcohol and dancing. We hired entertainers for the kids too which was nice. Cake, camera men, balloons, decorations etc. All in all about 7k+ I reckon, tried to talk the wife out of it but I had no chance haha.