Ladies Dearfoam knit booties reduced to £4.76 @ Costco MILTON Keynes.
Stacks available. Sizes are S/M/L.
Colours include red, blue and grey.
More details here on Amazon US website:https://www.amazon.com/dp/B01KY0E22M/ref=twister_B01KY0E1VE
Seems like a good deal!
Can be worn inside and outside.
May be available at other locations, didn't check!