A village hall for large numbers. Our village hall already had some games already etc. To make it cheaper can have a crafts table, hair styling table etc. By the time you play a few games, musical statues or pass the parcel, and eat food, it’s big a drastic amount of time to occupy and often they’re happy to run around and dance etc. With such high numbers a bouncy castle seems dangerous. Plenty of people/organisations do face painting, entertainment, balloon crafting, etc.
Make it clear what your expectations are with siblings. Some people just assume they can bring others and numbers multiple very quickly!
State on the invite that you are not providing party bags if that feels too expensive.
Food is clearly more tricky for a village hall as you can be left making sandwiches etc. or ordering food. It’s easy to make far too much.
With that many invites if you do whole classes, expect quite a lot of parents to simply not get back to you. Could make it clear on the invite too that if you don’t reply, you’ll assume they are not coming to the party! Otherwise it will be very difficult to cater for if you don’t have any idea of numbers.
More expensive option is soft play, local sports centres etc as they often charge a lot per head. No way I’d do that.
Nursery seems too young for all class parties…
Other options are just soft play etc for a handful of friends each.
Don’t worry what other parents are doing. It’s likely none of them gave twins and have double the cost! Some people do smaller parties and some whole classes. Nobody thinks anything of you or your children if you do no parties / family only, small or big parties so just do what you and your girls want!
The only thing you shouldn’t do is invite most of the classes and miss children out. Best to a small party with max 3-4 children each or a whole class party.