What do you already have? That would be my first question. I have used old clothes that I already had on hand and then added an other layer that was an old windbreaker anorak over top. I will give you a list of things that I have worn in the winter all of which you may already have or can cheaply get thru a used clothing store/ebay:

Wool sweater
down vest
fleece vest
polypro turtle neck shirt or sweater
arm warmers
winter ski jacket
neck wrap
used gore tex coats

In other words those things that will not absorb water. Top with a hooded wind breaker jacket (except the gore tex because it will stop the wind) that is large enough to cover the maximum number of layers you would ever need. I like the hooded ones to cover the ears and sides of the head.

In my opinion, the problem is not the temperature but the wind. Stop the wind, except as needed for ventilation and you will be warm.

One neat trick I want to try is the bandanna made of fleece. Put it over your face, cowboy style, to keep the cold air from hitting your checks and mouth. It directs the moist air down and away from your glasses.