Di has prepared a third tutorial. This one is fab - it's all about how to cut different materials using your Silhouette and how you adjust your setting for each. Di has covered adhesive cardstock, paper and vellum in this lesson and includes screen shots of the settings required for each medium.
Quickcutz are adding new designs all the time so keep an eye on their site too.
And if you are interested in purchasing a Silhouette, ask your local scrapbooking store if they would order one in for you.