Much of my early record collection was obtained by visiting flea markets and yard sales. It was typical for parents to put the LPs in milk crates and sell them for like a buck a piece. Often they had no idea of the true value of them. Got some really vintage stuff at the expense of those poor kids!
Speaking for myself, when I went to the military, I was never to see my baseball card and MAD magazine collections again!
My family was a little different. Never threw out anything. I got magazines and newspapers from the 20s on up. So much stuff.
I still have my matchbox car collection and comics.