Ships in Star Citizen may be purchased either with real cash, or in-game currency (aUEC). Ships purchased with cash are called "Pledges" and are permanently attached to your Star Citizen account. These purchases help fund the development of Star Citizen and Squadron 42.
Pledge ships can be bought as standalone purchases, as ship upgrades, or with game packages. The first option results in a ship being added to an existing RSI account, but it does not give access to Star Citizen (this makes it most useful for existing backers). The second option replaces a ship that is currently on an account with a more expensive ship while charging only the difference in value between the two ships. The third option includes access to Star Citizen with the ship purchase.
To purchase ships using real currency, see: Pledge Store
Ships have different availability for various reasons, set by CIG:
- Always available - Common
- Time-limited - Uncommon ships - put on sale from time to time.
- Quantity-limited - Rare ships - Batches of ships offered for short periods.
- Promotion only - Only purchasable through promotion offers
- Not available - Certain alien or military exclusive ships.
All ships being earnable in-game on release, there is no need to spend real cash on them, unless you wish to support to game, and even less so any need to purchase limited ships on the grey market.
Ships can also be purchased in game, using aUEC, earned from in-game activities such as Mining and Cargo hauling. These purchased ships are fully available for modification, painting, and destruction.