I have a Carhartt Kalkaska down parka I wore when I lived in southern Minnesota. Awesome parka that now has sadly been discontinued. Not sure if they make one similar nowadays but Carhartt is definitely worth a look if you're trying to keep the price down.
Layers are also really the key to staying warm in sub zero weather. I had a set of underarmor that I'd wear when I was going to spend more than 15 min outside in the depth of winter. Very helpful.