Why OOP?

Why is it that

(a) my role-playing group only wants to play Out of Print (OOP) games

or

(b) I want to only run games which are OOP?

Now my last game I ran was Werewolf, which proved expensive, but I managed to get all of the books I needed, plus some others. Next on the agenda is Deadlands. Do a search on Ebay, and you find zip, nada.