I usualy make my own with the biggest 80 perc wool socks . i layer an emergeny blanket and a thermal layer inbetween the socks . cut a hole in the bottom and sew the edges of the hole tight around the cleat area
i works really well but my feet get cold but not as cold . i can make them as cheap at 15 usd or 50 usd .
Ive seen some one use wool boot inserts i might try those next year .
I use lake boots for commute they work well but cost a bit
i was thinking of getting some fizik winter shoes for road but inthink my hack works well enought that i can do some outdoor riding during the day and a snlpin session at night indoors .