https://beaumont.craigslist.org/tls/d/n ... 56582.html
Here is a Craigslist offering for PTWFE and the self-study course. I've seen this ad for quite some time, and just verified with seller that it is still available, because he doesn't want to ship and has had no luck locally. Not in the best of shape (at least not the cover of the hardbound book anyway), but should be usable. Appear to be same vintage or editions as my copies from 1980.
Not sure if seller will sell separately, or if seller is aware of USPS Media Mail, which is much less expensive and books without advertising should qualify.
You might want to add your location to your profile, so others in your area may be of more help.