Might help if you told us a little more. Like what brand BCG are you looking for? What face size are you looking for (AR15/AR10)... etc. If you don't care about brand or quality- Sportsman's Guide has a no-name BCG on sale right now. That might be up your alley. If you want to give us a little more specifics as to what you're looking for- I'm sure someone here will be willing to help you out. Could always check the For Sale section here too.
jakhamr81 had some WMD's coated in Nickel Boron. I got one and it is top notch. It cost more but all you have to do is pull it out, wipe it off, and throw it back in.