RE: BRRRRRR
Polypro undies, tight fitting wool sweater, tight fitting fleece shirt, polypro balaclava insulated bibs, 2000 gram insulated boots, wool sock liner and sock and a wool hat are what I use down to 15degrees. If it is colder I wear a 2nd sweater. If it is windy, though my outer layer is something that will stop the wind.
Most of the stuff canbe bought from army/navy surplus.