I think, but mind you this is only from casual observation, is that there are several versions on each title. Many there are. maybe, 50 to 100 different publishers of free Tom Sawyer books. I'm sort of confused if you are asking about free Classics available on Kindle, or just the ones published by Amazon. Truthfully, I've found a lot of format errors in the ones published by Amazon and avoid them, but that is just me.
Re "50 to 100 different publishers of free Tom Sawyer books"
Thanks for your response. Mark Twain is one of my interests. When I search the Amazon.com "Kindle Popular Classics" freebie list,
http://www.amazon.com/s/?node=2245146011, typing in Tom Sawyer brings up 30 results. Is there something I don't know?
Re "a lot of format errors"
I agree; lots of formatting errors on the free books I've downloaded. But, I don't mind. If the item's readability doesn't satisfy me, I toss it back (i.e., delete it from my Kindle). So far, the majority of my downloads from the "Kindle Popular Classics" freebie list have been reasonably satisfactory; they don't have to look pretty, just readable -- that's me. My "complaint," observation, really, is that, at page=400, the same 10 titles are repeated, page after page, presumably, for the next 11,000 or so titles out of "16,480."
Freebie lover, here (I feel like I'm getting away with something).

elessee