That is the 64 billion credit question. And if I, for one, had a crystal ball, I would have bought Yahoo! when it merely sounded like a funny word (aww - heck - Monday morning fun: if you know the movie in which the word Yahoo! changes the future lives of a family, PM me. First right answer gets a prize.)
Sailgclass - you never know what item will be in high demand until after the fact. That's all part of the game. Although, I'd have to say, KrazyPete's guidelines aren't half bad - that yellow soldier is UGLY - and very coveted.