Should I buy Starbound now, or during the official release?

First up... the price for Starbound will likely stay at $15... as that's the pre-order price they set before the Beta versions EVER came out. So when it finally hits a final "Official" release, you'll likely be able to get for $15 as well.

HOWEVER, if you pre-order it from the developer's website directly, you get BOTH the Steam version (where the beta currently resides) & the DRM-Free version (which will be available once they're closer to an official release version) for the price of the game... or think of it as 2 copies + Soundtrack for the price of one.

Second, treat this like "Minecraft" in terms of buying now or waiting later. If you buy now, you get to enjoy the game while it's still be developed. Granted there will be bugs & the occasional world wipe (to make stuff compatible with the major changes), but you get to enjoy the game NOW.

If you choose to wait, you'll get to enjoy the fully developed & polished game... but you're going to be playing catch-up with everybody who got into the game before you... which might make playing online a bit less newbie-friendly as planets on the server's universe gets explored & developed.

I recommend just buying the game now as you can enjoy the game right now & you'll get all the updates through the official final release. This way you won't have to regret NOW getting the game earlier (beyond the current regret that might be building with the current beta out there) & won't have to worry WHEN the final official release comes either as that could be months or even YEARS away (AGAIN, it was YEARS from the time Minecraft was first released for sale to it's "Official" release... so the same could happen here).

Ultimately it's your money & your choice... you'll buy it when you believe the time is right.

Official release

Buy it now, before the price raises.