If you still have the game you will get all updates completely free. The game has improved A LOT since day one. They have added a lot of features, more than I can count off the top of my head, and apparently more is coming soon. There is a story mode, players can own many many bases, cars, bikes, a capital ship, a whole fleet of frigates. Portals are working. There is multiplayer. One big issue that remains, though, is the lack of variety on planets (or rather, in their color choices). All in all they still look same-y after a bit. I think planets were a lot more varied during the Pathfinder era (an old update). But they will probably tweak variety sooner rather than later.
If you never played it again since the original release, get ready, though. Changes are huge.