I think there are some good deals at this site, so passing it along:
https://www.venturesurplus.com/They have a clearance selection for the well-used stuff. I always liked the look of the British DPM jackets, and they had one in my size for under $10, so I went for it. (Of course, the shipping doubled the cost...)
The Brits' idea of a field jacket is definitely a little lighter than the American version, and I like a lightweight jacket.