The free version is floating out there in the ether if it isn't on Steam. I personally think it's funny to be upset over this, as why shouldn't these guys be paid for their work? I played the mod a few years ago when it released and was very impressed by the amount of effort and work that went into it. They updated and changed things for the better in quite a few ways. Music, sound effects, graphics, pacing were very much improved(mostly) in my opinion and it was fun to go back and play a WAAAYYYYY better looking version of Half-Life 1 that I hadn't played since I was 11. It was like my minds nostalgic memories version of a very dated looking game right in front of me but actually looks as good as I felt it did as an 11 y/o. It was pretty bad ass considering it didn't cost me a single cent to play.
They put a ton of effort into the remake and not a simple up-port or reskin and it shows. They deserve to be paid for that if you're interested in playing an even better(presumably) version of the game that came out 2 years ago. All that said, money is more focused on an eventual GPU upgrade(980 Ti) and I won't be picking this up immediately, but those interested should definitely at a minimum, download the mod from a few years ago and relive some memories. I'm more curious(as I haven't looked into it) as to whom from the original mod team is still around/on the team and what they've become since then. Are they now a studio?