We go out every day.
Most days, it's to the park, or a walk in the woods, or a wander along the beach.
Once a week or so we'll head to a garden centre to see the fish and have a coffee and cake, or soft play, or something cheap ish like that.
More expensive trips (sea life centre, zoo, farm park, etc) is much less often, 2 or 3 times a year or so, normally during holidays.
Last summer, we had financial issues, so spent the entire school holidays out and about doing free stuff. All it cost was diesel and packed lunches. And we were probably out 5 days a week, the other 2 days would be to a local (walking distance) park.
Saturday we went to a local country park to feed the ducks and see the squirrels. Yesterday was a walk in the woods, with a picnic on the bench (in the rain...). Today, we've been to the shop, baked some cakes, and after lunch we're going to walk to the local caravan park to have a play in the park (about a mile away).
If we don't get out, the dc start bickering, they make a mess, and eat me out of house and home. We're all much happier once we've been out for a couple of hours.