I need to buy a winter work coat, help?

Take a look at Gemplers.com. They're an ag-supply outfit and have the largest selection of Carhartt I've seen, as well as several other brands of work-wear. I owned a Carhartt "chore coat" with the blanket lining when I was in the construction trades and worked outdoors all day in some bitter weather with no problem. A bit of advice - when it comes to something that involves safety (think frostbite in this case), it's better not to go with the lowest price. You'll likely get what you pay for.