I like the new shiny, and I’m fifty, my home is full of stuff – I don’t need to go routing about for stuff I didn’t buy in the past… erm, except for one or two boardgames.
I missed out of the last copies in the shop of Fury of Dracula and when into my FLGS to pick up one of the two copies I knew they had, the week after Wil Wheaton had done a TableTop episode all about it, consequently, they were sold out. I also bought their last copy of Ikusa, previously known as Samuri Swords, previously known as Shogun for a mate’s 50th. WE played a game at my house before I let him take it away, and my son loved it so much (he won) that I then hod to find another copy.
Both of those I sourced through a rather lovely Facebook group: https://www.facebook.com/groups/RpgUK/?ref=br_rs . They do roleplaying games too, so getting back on topic, that’s one source that’s very friendly and well run. Its full of people looking for a fair price and and good home for old games, not profiteers hoping to make a quick buck.
My FLGS has a good stock of second hand RPGs too. But as I said at the top, my bookshelves are full. And for things that I might want as reference, PDFs are fine, so I am happy to but them on DriveThru (some which I guess are technically “out of print” if they are ONLY available as PDF), or when I want to look up something really old (like the exponential power mechanic of the old DC Heroes RPG) I’ll look it up on Scribd.