Good question. In the early to middle 1990s I produced and annotated a series of about 20 CDs of (mostly) previously-unreleased Newport material for Vanguard Records, but I don't know how many of them, if any, are still in print. I'd try typing "Newport Folk Festival" or "Live at Newport" into a search engine and see what you get. Some of them were single artist CDs (Phil Ochs Live at Newport, Judy Collins Live at Newport, etc.) and some were compilations (two bluegrass sets, one old-time, two blues, one folk general, etc.)