You can sell them on the Yaya's forum (someone might have the URL: I haven't been there for a long time).
I currently have several big boxes of workouts to get rid of.
The videos (yes, videotapes!), I intend to donate to Goodwill.
The others, I was hoping to sell on Ebay, but I haven't gotten around to it (I used to sell quite often on Ebay, but it's been over a year since I've done so, and I'm out of practice. I also dread any changes made that make the process harder). I could pay a month's worth of my mortgage if I got an average of $5 profit on each DVD!
I've given some away to colleagues wanting to get into exercising, but I'd really like to get some of my investment back.
Like you, I don't want to trade, because there's nothing I want in their place! (though maybe I should start thinking of stuff I want that I don't have and try to trade: thing is, if I want anything, it would be something new that other people wouldn't want to get rid of yet.)