You'll sure remember that: A long time ago, you were a noob and had no idea of how good MtG cards really are and made a very stupid trade.
So, here comes my worst trade ever, which I made when I was about 10 years old:
The grandmother of my friend found 2 old MtG boxes from her son, namely from the year 1994, all in german, some of the first MtGs ever released in here. (I was 1 year old when those cards were released, so REALLY old cards!)
And there it was: Tundra, a dream of each MtG player.
But just try to read it's text: "(...)If a spell destroys one of these Land types(...)" what!? I didn't understand anything at all, so I gave it away for a... for a... for a... SEASONED MARSHAL!

Oh yes, (ladies and) gentlemen, I gave one of the best freaking MtG cards ever away for a card that does just one thing: suck.
Pfff, I still get angry when I remember that!

But, no matter what, the trade is over and there's no way to change it. But, I'd like to hear from you. What were your worst Mtg trades ever, when you were noobs? Post your worst trades in here!