There is some in Wales but most of them are in Scotland. They’re free to stay in, but people are welcome to make a donation to MBA association that manages and maintains them. Some of them can be damaged or left in a mess due to people mis-using them. But for most part they are really appreciated by hikers. UK often has pretty bad weather- and camping is restricted in most areas so I find them super helpful! They’re also fun -as often they are in secluded places, so it feels like a little break away! 🙂