Mine was when my Grandmother took me to a military base (Grandfather was in the Navy), and I remember seeing a rack of comics, and an X-men comic caught my eye.
I remember it was somewhere between 1997-2000, and it had Wolverine in his yellow/blue costume on the cover along with Cyclops. It wasn't for another few years that I started reading comics heavily.

I believe this was it, I'm not 100% though:

Can't believe we didn't have a thread for this yet! Thanks for starting it.

Answer #1: Detective Comics #552



When I was five, my mother used to take me to a local pharmacy as a reward for being good at the doctor, and I could pick any one toy I wanted. Already a massive fan of superheroes thanks to Superfriends, the Linda Carter Wonder Woman, and the Adam West Batman, I usually picked up the rubber superhero action figures they had there. One day, though, it occurred to me to actually get a comic book, so I picked up the only Batman issue they had in the spinner rack, Detective Comics #552. This was just bad luck on my part. Sure, comics were no longer being written for kids in the mid-1980s, but this issue didn't even have a familiar villain in it, and while I adore Doug Moench's run on Batman, even the adult in me finds this issue's writing overly verbose and inaccessible, while the art is clumsy and unclear. It's no wonder I waited three more years before trying comics again.


Answer #2: Batman #428


In 1988, when the media blitz erupted about Robin dying, my mom rushed me out to the local stationary store and ordered me to buy a copy of this. I read it and was really moved. I read it MANY more times after. Still, for some reason, that wasn't my impetus for getting into comics.


Answer #3: Batman #436-438



Shortly after seeing the 1989 Batman movie, my mother and I were at the local video rental (the front third of which had recently been rented out to an amateur comic dealer), and I caught sight of these on the rack. I bought them and was soon coming back, week after week, to get more, and this slowly led me to expand out to try other titles as well. I'm not sure how well I understood the comics (they weren't written for adolescents anymore), but I liked the IDEA of picking up a new story on a regular basis, so that became the beginning of my regular comic book buying in the late '80s and early '90s. Of course, that was a TERRIBLE era for mainstream comics, so I dropped out around 1994, as cover prices kept getting higher, speculation was overly rampant, I couldn't understand half of what I was reading and recognized the other half as being of abyssmaly low quality, and I just couldn't keep up (neither financially nor in having enough time to read) with all the hyped new "must have" books coming out.

Answer #4: Classic X-Men #1



In 2002, I was out of college and had recently pulled out my old comic collection for nostalgia's sake. Stumbling upon my paltry X-Men collection again, a passion was rekindled, and I decided I wanted to read these again, but, with all the references constantly made to past continuity in those stories, I quickly decided that I wanted to go back to the beginning and read it all. I began assembling a full run of the Claremont stories, sometimes by getting the original issues, sometimes by depending upon tpbs, and mostly via the Classic X-men/X-Men Classic Reprints. Classic X-men #1 was likely not the first one I bought, but it was the first I read, and I remember reading it like it was yesterday, my reprint of GS X-Men #1 there by its side as I began to realize just how much had been altered in that story.

That rekindled passion for the X-Men led me to construct a paltry website (It's still up, but I am NOT posting a link), as well join the CBR Classic Comics section, and that got me into most of my other comic collecting interests. Then came this place

I am not quite sure. From nursery school on, I got a quarter a week allowance and I would be allowed to pick out either a comic book or a pack of baseball cards and a candy bar with it when we went to the local pharmacy (it was next to the gas station my dad went to, so I would go whenever he filled up the tank). 

The earliest comic I had in my collection that I remember was this one....




and I would have been just about to turn 4, so it was right around when I was learning to read and getting ready to start nursery school,so it was likely the fist I bought, but most of the comics I had were from about a year later, so it's possible I was given this instead of buying it with my allowance.

-M

I know I read previous comics that were bought for me. This one took half my weekly allowance

That was the first "new" comic I bought. I had been exclusively buying from the quarter bin at that point, and I was becoming a Batman fan already. In particular a Robin fan, because Robin was a kid like me. So one day at the comic shop while rooting through the quarter bin with my mom I saw this on the new comics shelves and begged her for it. She griped about the price but gave in, and that was my first new comic.

What is my prize for the most classic first comic in this thread?