Ebay is a good place to look for used, as is the Lightfighter Tactical Swap Meet
Note, with the Lightfighter Swap Meet, do not post a "want to buy" as its set up only for those looking to sell or trade kit.
http://lightfighter.net/eve/ubb.x/a/frm/f/3076001271
Personally, I'd just pony up the cash and contact Tactical Tailor or Dave's Army Surplus a call and get one new. You'll probably spend a long time waiting around here for one.