Hmm...Mine was in 1999, whichever NDK that was, I just remember I was a freshman in high school. It was at the old hotel, before the Holiday Inn, and I remember going in, buying a one-day badge by myself (didn't have any anime friends then), and buying a Mokona from the dealer's room, back when Mokona was still only from Magic Knights Rayearth.
I still have and <3 my Mokona. I remember getting to my parents car and showing them, and my dad asked "You bought a grinning marshmallow?" XD