The internet makes it possible to distribute large amounts of media for free. It's interesting to see the different approaches taken by organizations.
The Ludwig von Mises Institute provides audio or video of what seems like all of their conferences for free. For example, David Gordon's recent series on The History of Political Philosophy was posted on its website within a day or so of each lecture. Religious organizations also provide large amounts of free material, much of which is of interest to those who don't share their perspective. Reformed Theological Seminary has a number of free course lectures. I've been listening to John Frame's lectures on the history of philosophy and they are quite good. Also worth listening to are Knox Chamblin's lectures on C.S. Lewis.
The Ayn Rand Institute has only a limited amount of free stuff. They have recently posted some free lectures by Rand and others, available to registered users. Most of ARI's material is quite expensive. The Teaching Company's slickly produced courses must be half the price of ARI's lectures, and you can download them and save shipping costs. The Teaching Company's courses I've heard are excellent, if a bit self-consciously "middle of the road."
I'd recommend Prof. Daniel Robinson's course Great Ideas of Psychology which is excellent, if a bit chatty in places. (When the course is on sale you will be able to download if for considerably less than $100.)