Yeah, I love Goozex, but it's not good for getting rid of 100 DVDs.
DVDs tend to move slowly on there in my experience. Guess most people want Blu Rays--so you have lots of people ditching DVDs and requesting Blu Rays.
Craigslist is probably the way to go. You just have to accept that you're not going to make much per disc as used DVDs mostly have very little value these days with how cheap prices are on catalog (non new release) titles new and people moving on to Blu Ray.