DD works at Maccas and often does the parties. Its about $8 per head (when she gets home I'll ask her exactly) and you get a party room and a hostess who plays the games with the kids and does everything. You get 1 1/2 hours in the party room and an icecream cake as well from memory, also every child gets a treat bag and hat, the birthday child gets a better bag.
DD always says that 3 is the very minimum age to have one otherwise they are too young to play the games.
If you have any more questions feel free to ask and I'll get Jess in here to answer them
BTW they also give you invitations