Days out do not have to be expensive, nor do you have to forsake them when living frugally. Some fantastic days out cost no more than the petrol or bus fares used to get there (or maybe you could walk depending where you are and your chosen venue!).

Picnics:
Pop some filled rolls or sandwiches, fruit, biscuits, juice, crisps etc. into a bag and head off somewhere nice. City parks are free and can provide an entertaining day out - they often have free events on during the summer months from outdoor concerts to acrobats. Country parks are much the same though often much bigger and better for long walks. Beaches are great - ask about good ones at your local Tourist Information Office - they are not always the obvious ones where everyone goes. One of the best family days out we ever had was at a quiet country beach with a very basic picnic.

All cities have some art galleries and museums that are free or extremely cheap to see round. Make use of them - you sometimes feel like you are seeing a whole lot more than you ever did once you try to be frugal ;) If you are visiting attractions that make a charge try never to pay full price. Tourist information centres, libraries and many museums etc. will have leaflets advertising local events and attractions which often include discount vouchers.

Many cinemas have an 'early bird' deal every day - for films starting before 12 noon tickets can cost half to a third less than usual - this varies greatly from venue to venue but it's worth checking. Some cinemas have a cheap night instead.

Car Boot Sales:
Have a day out and make money for your next outing! Look around your house and loft. Is there a load of stuff that you don't want anymore? Try not to be too sentimental about this and do not dismiss stuff as 'rubbish' - you could earn several hundred pounds doing a car boot sale.
Old videos and CDs are popular items. Books are quite good sellers too (though check Amazon Marketplace or eBay below first - you could probably get more for them there unless very tatty) - asking prices seem to be around 50p for paperbacks and £1 for hardcovers. Toys are popular too - children will lead their parents over to your stall! Hideous (very) clocks, pictures, vases and ornaments will sell fast and people may even fight over them! If you grow plants these can sell also at around 50p each.
Obviously you make more money at the bigger regular car boot sales especially if you are willing to brave the cold. Summer weather means you will have a lot of competition. Watch out for the large group of resellers (sometimes fondly referred to as vultures) who will descend on your boot as soon as it is opened - it is good to have someone with you - one of you to unload and one to watch the clientele!
So go on, have a competition with your partner or mates, see who can come up with the best time for the least cash!