My winter gear is actually less expensive than my summer cycling gear. Why? Because I can wear whatever I want to wear under my jacket and sweatpants or splash pants.
A few tips:
#1 - Check the sales at places like Nashbar and Sierra Trading Post. Any cycling specific winter gear I've purchased has been purchased at those two places ... on sale. I've got my cycling tights, long-sleeved jerseys, and cycling jackets there. Oh, I did get one cycling jacket (a rain jacket) at MEC ... and my helmet cover and my current booties. I think that's pretty much all the cycling-specific stuff I have for winter. I get all my polypro from Sierra Trading Post ... two of the tops were $5 each, and one really big thick one was about $12. When I wear that, I can ride on freezing cold days and feel like I'm in the comfort of my own living room. I simply do not feel the cold in it.
#2 - Browse your local thrift shops. I have a whole collection of merino wool tops acquired at Value Village for about $5 each.
#3 - Go to your local department stores. Department stores often carry a wide range of great winter cycling products ... if you know where to look. First, go to the
hunting department. Hunters are outside for hours and hours in cool - cold conditions of the fall and early winter. They've got some good gear! You can get great wool socks, wool flip-top glove, neoprene gloves, those little chemical warmer things ... all sorts of stuf. Second, go to the
underwear department (both men's and women's). I took a cruise through the men's underwear section of a department store today, and noticed that they had base layer tops (antibacterial, wicking, etc. etc. polyester/spandex) for $10. I have one already, and love it, but I might pick up another one later. The men's departments also have the Kodiak socks ... the really heavy wool ones that come to your knee. Those are THE BEST socks!! I wear them while cycling, and in general all winter long. They run about $4 - 5 a pair, but they are worth it!! The women's section has the light wool socks which I wear at this time of year. They are a little less expensive (maybe $2-3 a pair) but are quite warm too. I'm wearing a $2 pair of cashmere socks today, which I got from Walmart ... very nice!

Then head over to the
sportswear department. You don't want 100% cotton stuff, but sportswear departments in department stores are often stocking stuff with wicking properties etc. now. I have a collection of "sweats" or "exercise pants" and that sort of thing which I wear over my cycling tights for a bit of added protection. That's also where I find my sports bras.
#4 - Visit your local Dollar stores. That's where I get all my winter accessories like my headbands, toques, mitts, gloves, neck gaiters, etc. They are each $1 so I stock up. You can get mitts and gloves from your local department store too, and those are generally a little better quality (and might run you $5 each). I use the Dollar store mitts and gloves as liners usually. The Dollar stores also have wool socks, so I've stocked up on a few of those as well. The quality isn't as good as what you'll find in a Department store, but they can be decent extra layers.
You can put together a good winter cycling wardrobe without breaking the bank ... you've just got to think outside the LBS. Be creative!