Spend the money on a full merino wool base layer, you will not be disappointed. Its warmth to weight ratio is pretty impressive, and it is very good all around at regulating your body temperature. As for brand I prefer IceBreakers, but there are a bunch.
Depending on conditions, I use any combination of:
Mammut SS underwear top
Minus33 Wool LS
Nike tight synthetic LS
Nike loose synthetic SS
Bottom gets Patagonia long underwear and either athletic shorts or fleece pants.
Cover that shit with a Patagonia Gore-Tex shell and some Trew Eagle pants and it's GOLD. Stay dry forever.
When I lead ski trips I have to help people with packing/layers every time. I see a lot of cotton on people at first. You avoid that stuff like the plague in the backcountry, regardless of what the trip is.
they arent cheap but the Smartwool NTS midweights are the best i have ever used, and i have cw-x, Under armor, colombia omniheat (my second choice), patagonia, and kombi.