One place where SF/Fantasy classics in actual book format should be available are library book sales. However in my home town, which just reaped over $22K in used book sale receipts, the ladies sifting through the piles of donated books don't recognize these genres and tend to toss them into the dumpster. They really dislike the cover art!! Beautiful, pristine hard and softcovers of Norton, Zelazny, etc. They have no idea what their value is so they aren't part of the sale. Ironically, because I have an insider track at the library this is how I have acquired - for free when I have had the time to look - a number of books by that cadre of authors, nosing through the discard pile. I can't wait to see what is in that pile in 20 years!