Personally I think it's really cool because most of the time you get to choose the photo & inscription and you know it's going to be an authentic autograph when it arrives unlike a lot of TTM successes.
Some people think it's greedy of celebrities to charge for their autograph but the celebrities I've purchased from have been bit part actors who probably sign to supplement their income.
So far I've purchased from....
Margaret Kerry (Walt Disney's model for Tinkerbell)
Pamelyn Ferdin (Voice of Lucy Von Pelt on Charlie Brown)
Karolyn Grimes (Zu Zu in It's a Wonderful Life)
All three autographs are favourites in my collection as the inscriptions are nice. I definitely don't have a problem with purchasing
