I got it for $15 on Greenmangaming yesterday and I've been having a blast with it. I've only been playing in Creative mode so far so that I can get used to building things and see what is required where. The most fun is building things just for the sake of crashing them into other things.
I've got random cargo ships on, so I just keep stealing cargo ships and ramming them into other ships.
If you're creatively inclined, I'd say the game is currently worth the asking price because you can spend a lot of time building interesting and creative ships. If you're not very creative, you probably won't have much to do in the game yet.
