Sandringham woods with a picnic and ball - completely free, no parking charge. Lots of open green space as well as extensive woodland with signposted trails of different lengths. A free sculpture trail ending with a picnic / storytelling area and sculpture of the Gruffalo. They now have a leaflet free in the cafe for the children to tick the sculpture off as they are seen. Also a lovely long play area / trim trail made of timber with zip wire as well as a small section more appropriate for little (roundabout, slides swings.)
The beach, obviously!
Bircham Windmill is also lovely if living locally - pets to handle, sheep milking, old fashioned Miller's cottage with toy sack barrows and bags of flour, brass rubbing and veggie garden needing watering. You can climb the windmill if feeling adventurous and do a kiddies trail or bake bread for an extra charge. More importantly for us, a small enough to be seen at all times but big enough to run off steam enclosed area of grass with a mound to climb, swing, slide, small rope obstacle, sand pit, wooden house and ride on cars. I think prices are about £5 per adult and £4 per child, under 3s free (from memory so likely wrong!) We got a season ticket (April to Oct only as shut out of season) for £40 last year and used it loads, meaning each trip was only around £4. FREE ENTRY to: The Bakery, Tea Rooms & Gallery, Gift Shop.