What happens next?

How to plan a cheap children's birthday party
Choose a low-cost venue.
Before you decide the specifics of a party, like what to serve or who to invite, you'll need to choose a location for the party. If you're sticking to a budget, you'll want to find a venue that is either free or very low-cost.
If you're throwing a relatively small party, you can host it at your home or in your backyard. If the party will be too big for your home or yard, try booking a picnic area in your local park.