If you've got kids, you'll know they need entertaining. One way to do this is to buy an annual pass to a zoo.
I've just discovered it's cheaper to buy your annual pass through a zoological society rather than through a particular zoo.
For instance, adult annual membership for Woburn Safari Park costs £65. But if you buy annual membership through the Royal Scottish Zoological Society, which admits you to a whole host of zoos around the UK including Woburn Safari, it works out at £65 for TWO adults (ie £32.50 per adult). And instead of paying Woburn's price of £55 for a child's annual pass, it's £30 with the society.
You soon get your money's worth if you go on a couple of zoo trips.