There's only white and black, but the white has a faint greenish tinge (some people claim it's turquoise) so people get confused and think it's a third color. The white ones generally sell for more, because there are not as many of them, but the black ones are supposed to be slightly better at sewing. I think price depends mostly on whether the seller knows what the item is (ridiculously low prices from those who do not know, and very happy buyers) and on whether, knowing what it is, he jumps to the conclusion that it's made of gold (ridiculously high prices from those sellers, but usually no buyers).