Fleet Ship Modules can be bought in the C-Store for 500 
and are required to purchase certain Fleet Ships in both the Klingon Empire and Starfleet faction Fleet Starbases. Fleet Ship Modules are single-use items that otherwise have no restrictions; they can be traded, mailed, and bought or sold through the exchange. Once used or resold, Fleet Ship Modules cannot be reclaimed.
The number of Fleet Ship Modules required to purchase a Fleet Ship will vary based on the ship, other ship unlocks on your account, and other factors. Normally, fleet ships cost 20,000 
and four modules; exceptions to this are the Fleet Advanced Heavy Cruiser Retrofit, Fleet Dreadnought Cruiser, Fleet Caitian Atrox Carrier, and the B'rel Fleet Bird-of-Prey Retrofit, which cost 20,000 and five modules.
If your character already owns the tier 5 C-Store version of a ship (2000 ), which is often a retrofit of a lower tier ship, then the respective "Fleet (Retrofit)" will only cost 20,000 and one module. If the base ship is already tier 5, then purchasing the C-Store refit of said ship for 2500 will trigger the discount instead. Similarly, fleet versions of the 1000-day Veteran ships, such as the Fleet Chimera Heavy Destroyer, only cost 20,000 and 1 Fleet Ship Module, but may only be purchased by 1000-day Veterans.
Discounts
The following discounts are account-wide, but only apply if you purchased the ship from the C-Store. Ships received by any other means, such as from a mission reward like the Support Cruiser Retrofit, or any ship claimed with a Vice Admiral token, will not activate the discount.