Lifetime Membership for £99 @ Hostelling Scotland (previously SYHA)

Haven't looked to book in Scotland this year, but did stay in Stratford YHA, in the summer for the commonwealth games for 1 night and only booked it 2 days ahead, which came to £44 for 5 of us, which was very reasonable! Decentish food and the women's England footy on in the bar that night, then used the self catering kitchen for breakfast before heading to the games.

Even if no longer cheap, we're limited as we have 4 children (1 was away elsewhere in July, though). I'll need to check if still true, but Scottish membership used to give discount in England and Wales, too, plus abroad, as I have been a member of both over the years (not at the same time!).