My current Amazon account says that my first order was a DVD of Office Space on September 15, 1999.
I have another Amazon account associated with an old e-mail address that I apparently opened in 2000. My first order on that account was "The Remains of Tom Lehrer" box set of CDs on May 24, 2000. From those two orders, you'd think I never order books from Amazon, but I really do.
Interestingly enough, when I did a search for my name on Amazon (not in the right place to find my old account, but just in the regular search bar), I found a vanity published book I co-wrote with a concert photographer back in 1994. It showed up listed as a "rare oversized soft cover" book which sold for $85.
I still have two copies of it in my portfolio, so it's nice to know that I own something I could sell for $85 if I ever get short of ready cash.
So when was your first Amazon order and what did you buy?