So they're not boot socks literally, but they do give off a great appearance your wearing some.
All I did was took a little trip to Goodwill, found some old ( cheap)
sweaters and cut the sleeves off !
When choosing sweaters there are a few things to look for.
1. Fabric that won't fray easily.
2. Make sure arm holes are stretchy.
(you want then to fit up your calf)
3. Make sure the fabric isn't too thick.
( if your boots zip up you don't want a really chunky cable knit you can't put your boots over)
Remember, if your a sewer you can sew some actual socks onto the bottoms of the sleeve and voila, boot socks !