If OP doesn't update the first post in a couple of days, I'll make a new thread, seeing as I sorted all the games by compatibility and the cretin hasn't even bothered to update the list with it because it involves a modicum of work on his part. That is, if no one has any objections.
Plus I'll sort and add all the new additions too
Alpha has never been free; and unless you kept a backup of it from before beta the only way to play alpha anymore is by pirating it.
I know this is way nit-picky, but Alpha was free for a weekend back around September. Notch had a problem with his servers or something and decided to make it an impromptu play for free weekend.
So, theoretically, if you don't care about playing online, and didn't want to update at all, you can still play that old version just fine, providing of course that you downloaded it during that free period and pirating it.