These genuine sheepskin insoles are on sale for $15 on Amazon - but hurry if you want warmer feet!
Amazon.com: Novforth Warm Insoles for Shoes, Women Thick Sheepskin Insoles, Mens Fleece Inserts for Boots Slippers Wellies 6 M US Men/8 M US Women : Health & Household
Sheepskin Insole - Ugg (US)
UGG Premium Sheepskin Insoles for Men – The Insole Store