This has become a pretty good business for some states and a handful of retailers. I worked in a store in Berkeley CA last summer that bought SAKs by the pound. The knives cost the store pennies. We sold em for low prices after they were cleaned up; SA Classic = $3.99ea.
I had mixed emotions selling someone elses lost knives but I used it as a platform to show the customers just how stupid the whole TSA prohibited list actually is. We would have a candy jar full of Classics and another full of LM micras; I would show folks just how less safe they are by showing how much time the TSA wastes on little knives and scissors.

Another issue here is that the original owner paid the sales tax but these confiscated knives are earning 2nd and 3rd sales taxes plus the money the Gov't earns on the sale. There was an article about PA in one of the knife magazines with a headline that read "Taxation by confiscation without representation".

An interesting point is that PA state law prohibits the state government from selling dangerous items to the public. When asked about selling the TSA confiscated knives the state spokesperson said they did not consider the knives to be dangerous; but the TSA who confiscated them did. Odd.