I remember Toys R Us used to sell bags of older comics. I probably got some as a kid but I couldn't tell you which issues.
I did have FF #197 and reread it many times as a kid. I probably bought it off the spinner rack at the grocery store. I was dropped into the middle of a story and didn't know what was going on. Reed was depowered, had to recreate the experiment that originally gave him his powers, which also recreates the Red Ghost, some obscure old villain I guess. I liked the fight between the two and Reed finding many ways to use his powers. That's what I often found interesting about comics, the many different applications of one superpower.
Since I got the comics when I was 4, basically before I could read, I had to deduce the story from the pics. It wasn't too bad of an intro to Mr Fantastic since he got repowered, so I learnt what his powers were.