I like to etch circuits, mess around, and learn. I don't care to mess with SDR stuff or buying anything. The art of building is far more interesting than the end goal IMO.
Well there are some Doug Demaw books on scribd.com which might be of appropriate vintage ( QRP classics or W1FB Design Notebook for example ). Maybe search 'QRP' in the books section of archive.org but I'm not so confident on that one.