Venue where the party will take place is very important towards cutting cost; choose a central that is easily accessible to all that want to attend. Then after the party is over let everyone be involved in cleaning up, at the end of the day you'll spend a very minimal amount and still fully enjoy your holidays.
If you choose to travel to the country side use public transport rather drive yourself; will even give you a chance to enjoy the scenery. If you are one of those who do not like large gathering transforming your living room to a theater may just work wonders. Rent movies that the whole family will enjoy not forgetting that bowl of popcorn, nuts and drinks. Alternatively you can cook where the food is healthier rather than going to a restaurant where mostly you'll get junk food. This would be a great opportunity to experiment new recipes with your family and enjoy each others company in the kitchen. As I say it would not hurt to be a little adventurous, by letting the children bake different shapes of cakes. Allow them to have scopes of ice-cream and chocolate that is bad for their teeth for once, anyway it is a special day.
It would be incomplete not to mention picnics as the other great way to enjoy that special day. These can be done in parks which do not charge for the venue or at a home garden. As you have seen there is really no reason not to cerebrate that special day with economic slump. Either way even with the little resource available you can maximize this holiday season. I personally opt to have a ball this coming holiday.