If you have followed the path of the Atlas in No Man's Sky, you may already be carrying a few Atlas Stones. While the game never really tells you what to DO with Atlas Stones, we now know what the deal is. (Some spoilers ahead.) Yes, Atlas Stones sell for a pretty penny, and at first, you're likely just going to get rid of them -- inventory space is precious in No Man's Sky when you're just starting out. By the end of the game, however, you want to make sure you have 10 Atlas Stones in your inventory, before you decide to visit the centre of the galaxy. This is all predicated on the idea that you want to play No Man's Sky while guided by Atlas of course; if you have no intention of following the standard progression path, then feel free to get rid of all your Atlas Stones and to carry on as you see fit.
If the idea of keeping Atlas Stones sounds ridiculous, do note that you can vastly expand your inventory space as you play; the most I've seen is dozens of spaces for your Exosuit, and that's without counting whatever space you may have on your ship.
As we noted in our tips post, a quick and easy way of getting more slots is to seek out Drop Pods on planets, or to purchase whatever Exosuit upgrades you may come across while on your travels.
If you want to know more specifics of what 10 Atlas Stones can actually do, keep reading. Otherwise, let this arsehole dinosaur who tried to kill me once act as your final spoiler warning.
OK, so: When you complete your journey with Atlas, you have a choice. You can continue to explore the galaxy, OR, you can birth an entirely new galaxy using 10 Atlas Stones. Making a new galaxy is, as far as we can tell, the closest thing No Man's Sky has to "beating" the game, but really, getting to that point just starts everything over someplace new, as you'll see below in RabidRetrospectGames. Fast-forward to the 12:05 mark if you want to see the "ending"; the rest of the video is the full Atlas path.
Depending on what you're playing No Man's Sky for, getting to the centre of the galaxy may not appeal to you at all, in which case you shouldn't worry about Atlas Stones. Just sell 'em. That said, looking at the video above, it really does look like the payoff is nice. I mean, you put in all this work to find out "what it all means", and this feels like an appropriate answer to that.
It means nothing. It means everything, again and again.
Also, the 65daysofstatic track that plays when you create a new galaxy is terrific, and worth the price of admission alone.
Kind of wild to think that the opening moments of the game, after you wake up in a crash landing, may have been the result of another galaxy birth. Damn.