A family day out always sounds wonderfully simple.

“We’ll go somewhere nice with the kids.”

Lovely.

Then you've paid for parking, bought three drinks because nobody wanted the drink they brought from home, and somehow acquired a small plastic dinosaur from a gift shop.

It's 11:47am.

Fortunately, a day out around Peterborough doesn't have to become a minor financial event.

There are places where admission is free, places where your main expense is parking and others where you can pay one family price and know roughly what the day will cost before leaving home.

Here are four worth knowing about.

Peterborough Museum: free, indoors and conveniently central

Let's begin with a word parents don't hear often enough during the school holidays:

Free.

Peterborough Museum & Art Gallery on Priestgate offers free admission and is normally open Tuesday to Saturday from 10am to 4pm.

For families, there's another important advantage: it's indoors.

That's worth remembering when the Peterborough weather has looked at your carefully planned outdoor adventure and decided otherwise.

Because there's no standard admission charge, you also don't get that slightly stressful feeling that you must extract six solid hours of entertainment from the place to justify what you've paid.

Have a wander. See what the children find interesting. Stay longer if everyone's enjoying themselves. Leave when they're not.

Revolutionary, really.

The museum does point out that some special events and exhibitions may have a charge, so it's worth checking what's on before you go.

But for an ordinary visit, the entrance fee is precisely £0.

You could even bring lunch or combine the museum with another city-centre stop.

Just be aware that the money you've saved on admission may make a surprisingly persuasive argument for cake.

Ferry Meadows: bring sandwiches and let them run

Some family outings need activities, schedules and tickets.

Others mainly need a large amount of space for children to burn off energy.

Ferry Meadows in Nene Park falls very nicely into the second category.

There are lakes, woodland, walking and cycling routes and three play areas, so you can make the day as ambitious or as lazy as everyone feels.

There is no admission charge if you arrive on foot or by bike.

If you're driving, parking is the main predictable expense.

 Charges run from £2.60 for up to an hour to £7.80 for stays of more than eight hours.

The beauty of Ferry Meadows is that you can bring most of the day with you.

Sandwiches. Drinks. Bikes. Football. Picnic blanket. An optimistic amount of fruit that everyone will ignore in favour of crisps.

Once you're there, you don't necessarily have to keep spending.

Of course, there are optional extras and places where money can leave your wallet if you let it.

That's true of almost anywhere involving children and ice cream.

But pack a lunch and Ferry Meadows can be a very manageable family day out.

And unlike somewhere with an expensive entrance ticket, there's no pressure to stay until closing because we paid for this and we're going to enjoy it.

If everyone's tired after three hours, you can simply go home.

Flag Fen: £20 and you know what you're spending

Free days out are brilliant, but sometimes you want an actual attraction to explore rather than another afternoon of telling somebody not to poke their sibling with a stick.

That's where Flag Fen Archaeology Park comes in.

The site, on The Droveway off Northey Road, offers a family ticket for two adults and up to three children for £20. Under-fives and carers are admitted free.

For a family attraction, knowing the main price before you arrive is useful.

There isn't the slightly mysterious maths of £14.75 for one adult, £9.35 for another person, £6.82 for a child unless it's a Wednesday, plus a booking fee and possibly your firstborn.

It's £20 for the family ticket.

Flag Fen also has toilets and baby-changing facilities, which sounds like an incredibly boring detail until you're travelling with small children.

Then it becomes one of the most important facts in this entire article.

The attraction gives families a chance to explore Peterborough's archaeology and history, and because the main admission cost is fixed, it's relatively easy to build a budget around it.

You'll still need to think about travel, food and anything else you buy, obviously.

But “budget family day out” doesn't always have to mean “find somewhere free”.

Sometimes knowing exactly what the main activity costs is just as useful.

Peterborough Cathedral: history without a hefty entrance fee

Peterborough Cathedral is another option that's easy to overlook when you're thinking about family days out.

Perhaps “Would anyone like to visit a cathedral?” doesn't produce quite the same reaction from children as “Who wants to go for ice cream?”

Give it a chance.

The cathedral normally welcomes visitors by donation, with usual opening hours of 10am to 5pm Monday to Saturday and noon to 3pm on Sundays.

Access can change because of services and special events, so checking before you travel is sensible.

For families, there's architecture, history, outdoor space and the possibility of adding a picnic to the visit.

And there's something rather nice about an outing where nobody needs to rush.

You can explore the building, look at the details, head outside and turn it into part of a wider wander around the city centre.

Tower tours are also available, although age guidance applies, so check the details if that's the bit you're particularly interested in.

For a straightforward cathedral visit, though, the donation-based approach means you can contribute an amount that works for your family.

Which one works best for your family?

It really depends on what sort of day you're after.

If the budget is particularly tight or you've reached that point in the school holiday where you've started regarding every £10 note as a close personal friend Peterborough Museum and the cathedral give you plenty to work with.

If everyone needs fresh air and space, Ferry Meadows is difficult to argue with. Bring your own food and the spending is much easier to control.

And if you want a more defined attraction with a clear admission price, Flag Fen's £20 family ticket makes planning straightforward.

There's no rule saying a good family day out has to cost a fortune.

Children, inconveniently for the enormous family-entertainment industry, can be perfectly happy with a playground, a picnic and permission to jump in something they absolutely shouldn't be jumping in.

The biggest money-saver is often deciding your budget before you leave.

Pick the main destination. Check the opening times. Bring drinks and snacks. Pack lunch if it makes sense.

And perhaps establish the gift-shop policy in advance.

Because negotiating with a six-year-old who's already holding the £12.99 stuffed animal is not budgeting.

It's hostage diplomacy.

Have you found a genuinely good-value family day out in Peterborough or the surrounding area?

Tell us where you went, roughly what you spent and the ages of the children.

The best recommendations are often the places other families simply haven't thought of yet.

Please add you thoughts below in the comments section