Mostly on eBay
and local monthly fairs.
Almost accidently, I have become interested in authentically used "commercial covers" and postcards.
With 193, UN members plus Vatican, Taiwan, Palestine, Northern Cyprus, Kosovo and the United Nations itself, there are 199 de facto nations/entities . Arguably 200 entities if Sovereign Military Order of Malta is included (and I don't include it). I now have mail from 177 nations with #178 on the way. I think it is so much better than used stamps taken out of context and obviously much better than CTOs. Obviously the remaining 21wont be easy....I might have to write personally to President KIm in PDR Korea and hope he replies.
All this and keeping up with Ireland new issues.
For me, Ireland is serious collecting and drives me insane...but the "world" is just for fun and keeps me sane.
Thus hovering between sanity and insanity, I am a well balanced man.