The only book worth anything was this old Linux textbook written in 1997. I listed the book at $15 (the lowest price) thinking I'd never hear back on it, especially considering there about a dozen other copies for sale. Today I got an email saying that the item had sold! Fine by me, it's $15 I didn't have yesterday.
I'm still a little confused why of all the textbooks the only one worth anything was an old Linux book. I can't think of many computer books at all that are worth anything after a couple of years. They become out of date so fast, especially a Linux book. It's an eight (8!!!) year old book!