Part of the fun of working with wool is the hunt of finding wool in thrift shops.Rug hookers call it 'found wool' and use it a lot as it provides texture to their pieces and can be easily over dyed to get a variety of colors from one textured piece. I like it for the same reasons in my wool applique quilts. In the piece I just started I am using a piece of found textured gray wool for a tree trunk. True you get different weights of wool,but that is part of the charm of the finished piece
I went to Goodwill in February and found several 100% wool jackets and pairs of pants. After washing the garments in hot water and drying in hot dryer ( kill any germs, get rid of dust and to slightly felt the wool) I then cut the garments apart. This way you can get a lot of good wool for a few dollars. It is even better if you can get some from friends wanting to get rid of wool clothes.
Here is the wool I got from a dark olive green jacket on the right ( true color is at the back edge) and a pair of brown tweed women's pants.
I got several gray and brown herringbone jackets which I will over dye and a great burgundy jacket, as well, which I will probably use as is because the color is great. I just cut off the waist band of the pair of pants and cut out pockets and the rest is easy---just take out the seams of the legs. If you start by snipping the thread of the seam for a 1/2" to 1" you can then just pull the seams apart. Jackets are a bit harder as you have to cut off the collar, take out the lining, cut off buttons and button holes, take out several seams etc., but well worth the time and effort.
I always make sure there is a 100% wool tag in the garment. It is getting harder to tell by the feel of the garment if it is 100% wool. A good test after you get home is to take a small sample of the fabric and try to light it on fire. Wool will not melt (as polyester) or burn (as cotton).
Enjoy the hunt!