Budget a family day at an amusement park.
Theme park tickets are the headline cost but rarely half the day. In-park food is the line families underestimate most: a meal, snacks and drinks for one person routinely reaches 30 to 40 dollars because there is no alternative once you are through the gate. Parking is a fixed charge per vehicle, and souvenirs are effectively a discretionary cap you set in advance or spend without limit. Setting all four out separately gives you the two levers worth pulling — eating before you arrive or bringing water, and agreeing the souvenir budget with children before rather than at the gift shop.
Amusement Park Budget
Tickets = adults x adult price + children x child price; food = party size x per-person food; total = tickets + parking + food + souvenirs
Roughly double the ticket cost. For a family of four with 70-80 dollar tickets, expect 450-550 all in once parking, food and souvenirs are counted.
Usually if you will visit twice or more, since most passes are priced at around two single-day tickets and often include parking — which alone is 30 dollars a visit.