I do them every now and then if the weather isn't nice or I'm up early before my friends. The most recent one I did netted me a $200 VISA gift card at the Vacation Village in Weston. They bought me a buffet lunch in Bonaventure Country club and then went thru a 2 hour sales pitch. The sales lady was pleasant and I was happy to make $200 for 3 hours of my time which included eating lunch on the golf course.

Carolinian is right, mention ebay and they realize they don't have a sale.
I like to talk timeshares so usually end up staying the full 90 minutes but if you don't engage them you will be done much sooner.

I had a sales agent ask me once after the free breakfast if I wanted my free money already. I laughed because he hadn't even started his sales pitch yet.
I guess he wanted to move onto a more lucrative prospect. Needless to say he wasted his day with me.