I have "new" cold weather riding gear.
Here are 3 merino wool sweaters that I picked at a thrift store.
I washed them by putting them in hot tap water with a shot of joy dishwashing detergent. I left them overnight in the water then rinsed each of them several times. Finally I put them in the washing machine on the spin cycle to get the water out of them and laid them out flat to dry. I don't think they were harmed from that experience even though they are marked "dry clean only". Dry cleaning can get a little pricey.
The red sweater is a fine merino that I modified to make a set of wool long johns. The brown one is a very fine wool with a turtle neck collar and goes under the green one. The green one is an old Brooks Brothers merino wool crew that is as soft as cotton but very thick.
I went for a short ride this afternoon with the temperature hovering about 45 degrees. I also was wearing a t shirt under the sweaters, a leather Fox
River Creek leather jacket that I purchased off Craigslist for less than half what a new one costs, and an old nylon warm up jacket over the leather jacket (the leather jacket leaks some air around the zippers, but the nylon warm up jacket sealed this out - and a pair of jeans. Also a pair of gloves and some old boots.
With some wind proof pants I think this combo would be good down to 38 to 40 degrees for several hours. Below that, I would need to add neck/head protection for any long rides.
Total cost of the three new pieces - 12 bucks. Add 5 bucks for an elastic waistband from the fabric shop. The band was sewn in to the waist to keep the long johns in the right place. Plus the time and thread it took to fashion the red sweater into long johns. So cash outlay was 17 bucks.
Pretty cheap and pretty effective. Here are some pictures.