I'm always having a look through op shops (thrift shops) for old game titles. I used to have a fair few big box PC games and going back even further, console games when I was young. Really wished I held on to them all! After watching a lot of YouTube channels (especially LGR) I decided to get back into collecting. Just odds and ends I can find on the cheap.
Some recent pickups.
There's 2 big stores right near where I work so I often have a quick look through on my lunch break. Treasure hunting is fun... although I'm going to need a bigger shelf soon! I wanted to start with PC big box stuff only as it's rare, especially in Australia, but I'll take anything game related.
One day I hope to attain Doom v1.666 the original big box PC version with the 3.5" floppies. Last one I saw on eBay was up to about $1300 AU...