Because Starsector is still in active development (alpha/beta phase), the primary way to acquire a new key is through the developer's official site.
The modding scene has exploded with "key new" content:
Your colonies no longer grow peacefully. starsector key new
The sector is highly dynamic, with a functioning economy, factions that wage war, and trade routes that you can exploit or disrupt.
Access all sectors, missions, and content without trial restrictions. Access all sectors, missions, and content without trial
If the game is still installed or was recently on your machine, your CD key is hidden locally in your system configuration files: Starsector » Preorder
The game is famous for its unique distribution model. Influencer SsethTzeentach : You can buy a key for $15
: A single key can be used on any number of computers you own; there is no limit on activations.
: You can buy a key for $15 (a 25% preorder discount) on the official Starsector Preorder Page .