My daughter needed a specific graphing calculator for school. They cost around $130-$140.
I got one on Ebay for $66 including shipping, and it's in good shape and works perfectly. It's even a good color.
$66 is more than I wanted to pay for a school supply, but it's a hell of a lot better than $140.
I read
somewhere that this graphing calculator has a faster processor than the computer on the first space shuttle.