Socks.

Stretch knit, so sizing is forgiving

Five styles, from knee-high stripes to soft everyday pairs, and all of them stretch knit — which makes this the most forgiving thing in the shop to buy without a measurement. A sock stretches across a range of feet in a way a shoe never will.

Knee-highs are the exception worth thinking about: how far up the leg they land depends on your height as much as your foot size, and the reviews are more useful than the size label on that. Every one of these is rated five stars, though on a small number of reviews. Returns are 14 days from delivery, unworn and with tags on.