My first comic was probably a Gold Key Disney or Looney Toons that I got in the hospital when I broke my arm. But the first comic that really cemented my love for them was this one:
When I was eight, a neighbor kid was selling magazines door to door for a school fundraiser. He was selling comic subscriptions, and my parents gave me the choice of either getting Spider-Man or Hulk. I went with Spidey, and a few months later, this issue came in the mail.
It was the second part of a two-part story. Maybe a decade later I found and bought the first part of the story. Really helped the issue make more sense.