FIRST QUESTION: Have you studied the basics of Mentalism yet. . . you know, those things called Books that teach the basics?
SECOND QUESTION: If so, why do you think you need a DVD? You already have plenty of information that will allow you to replicate most everything you're being charged too much for on the DVDs. Besides, in a book you get several dozen if not over 100 effects for about the same or less money than the DVD is going to cost you, an typically from more reputable sources.
No, I'm not saying that you shouldn't get DVDs, there are some excellent ones out there but it really depends on your experience level and where you stand education wise. I'd certain not recommend some of the John Riggs material that's out there to someone in their first two years of study while I would recommend some of the stuff Osterlind and Banachek have produced. . . the Banachek PSI Series being a very wise investment for that matter is is Osterlind's "Easy to Master Mental Magic". Jay Sankey has some wonderful stuff as well, but it's more commercially slanted -- tricks vs. technique and insights that will empower you in ways that go beyond "his stuff". This is true with most of the material being marketed these days.
If you want to learn Mentalism rather than Mental Magic or worse, mislabeled material that actually fits in with Bizarre Magick more than the others, then why don't you actually study Mentalism itself; toss the pop technology stuff off to the side and invest in printed materials that address this side of the craft; the works of Stephan Minch, Robert Nelson, most everything from Bob Cassidy and Richard Webster not to mention Al Koran and William Larsen, Sr. You will end up with far more pertinent material that will blow people's socks off, give you a means by which to create your own or improve upon what you have and most importantly, you will not be seen as another "kid" doing the same exact stuff everyone else out there is doing.
Think about it.