I was thinking of getting some of these to wear with ballet slipper type shoes in the summer, and I was just wondering if anyone had tried them and could report on whether they're worth buying? Whenever I've had similar things in the past, they've never stayed put, and I've ended up with a useless lump of bunched-up nylon under each foot. I just wanted to know if they're any good before I spend £6 on them.
Thanks!