I think the upcoming webinar is free. Perhaps you saw a link to purchase the V9 seminar DVDs? That said I have always thought Sony Vegas drops the ball on not having enough free tutorials to show people how their product works. Pro Type Titler is a good example. Adobe on the other hand is very good at that.
Well that is for DVDs which is understandable. I think the seminar series used to be online for free. Not sure if this is it but there are free tutorials here: