Don't ever go to a time share presentation. No matter what you are promised. These people are big fat lying liars. $100 for 90 minutes of your time? Yeah, right. More like 2-and-a-half hours, and they'll try to give you half the money at the end, and jam your cell phone, so no one can rescue you.
Don't do it, even if you think you might want to buy a time share. Because you don't. Anyone who can do simple math can figure that out.
Finally, if you ever do get sucked in to going to one of these things, bring a tape recorder. I'm sure they'll love that!