There are a lot of Lafferty Books I would love to own, but they are so rare, I cannot possibly afford copies. Some of them exist in libraries - mostly university libraries, and many of those libraries participate in the interlibrary loan system. So here is how I satisfy my jones for hard-to-find Lafferty:
1. I look up the book I'm interested in, for example Half a Sky, on Worldcat.org (http://www.worldcat.org/search?q=lafferty+half+a+sky&qt=owc_search). Whaddaya know, there are 22 copies listed in various libraries.
2. I go to my local library (Albuquerque Public Library in my case: http://abclibrary.org/) and fill out the interlibrary request form
3. I pay their $1 interlibrary loan fee, which I suspect doesn't even cover the cost of postage--I figure it is just an "are you serious" fee.
4. A week or two later, they call me to tell me the book is in.
5. I bring the book home, pour a dark beer, and read jubilantly.
I recommend this system. It works.