Fleet Ship Module
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 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.
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.