I live in Sisters Oregon in the shadow of the Three Sisiters range and just east of the wilderness area named for the range,and at an altitude of 3200 feet above sea level. I live in weather on a day to day basis that many would consider winter camping. Around here people wear blue jeans and cotton hoodies when its above 20 degrees. Every body wears either Sorels or tennis shoes all winter long and the down jackets are $80 affairs not marmot. Anyway we do stay pretty warm even though this gear isn't expedition grade, or is rarely breathable, BUT for the most part it is dependable and rugged enough to stand constant use for months on end. I wear cotton wool blend long underwear from the Bi-mart that can be worn four days in a row without becoming too smelly.
Anyway I noticed in the Cabellas catalog that they have down long underwear for $60 per piece. Most people have expensive coats and neglect their legs, for $60 you can have down pants. Also LLbean and other companies provide serviceable clothes to this market.
Jim