The Virtual Dealers Room
One of the best things about cons is the dealers room. Not only can you buy things you can't find elsewhere, but you can find some great deals.
The Virtual Dealers Room is a place to find short-term deals on ebooks, and you don't even have to have a membership. This is an author's cooperative; none of the proceeds go to the site. Authors (or publishers) are invited to post their sale items and everyone cross-promotes on social media.
I put this site together with my mad Drupal skillz. It's an experiment, so any and all feedback is welcome.
Remember the URL: thedealersroom.com.