Varying ship prices?

Solution 1:

Some systems sell ships and equipment at discounted prices. For example, all ships are offered for a 15% discount at any system controlled or exploited by Li Yong-Rui.

Here's a list of currently known discounts:

Discounts on Ships and Outfitting

All outfitting & ships
   Location: Li Yong-Rui Controlled and Exploited systems
   Discount: 15%
   Requirements: None

All outfitting and ships
   Location: Founders world (Shinrarta Dezhra) - All stations
   Discount: 10%
   Requirements: Permit gained via Elite rank or backer level

All Ships and limited outfitting
   Location: CD-43 11917 - Attilius Orbital
   Discount: 20% on selected ships, 30% on selected modules
   Requirements: Permit gained via CQC Prestige

Details on the latter (Attilius Orbital): https://www.reddit.com/r/EliteCQC/comments/3r6z3d/cd43_11917_attilius_orbital_discounts/

Discounts on Specific Ships

ASP
   Location: Alioth - Irkutsk Station
   Discount: 20%
   Requirements: Alioth Permit

Orca
   Location: Alioth - Irkutsk Station
   Discount: 20%
   Requirements: Alioth Permit

Diamondback Explorer
   Location: Wolf 406 - Hamilton Gateway
   Discount: 20%
   Requirements: None

Eagle
   Location: Sol - Daedalus Station
   Discount: 20%
   Requirements: Sol Permit

Vulture
   Location: Sol - Daedalus Station
   Discount: 10%
   Requirements: Sol Permit

Eagle
   Location: Beta Hydri - Edmondson High
   Discount: 10%
   Requirements: Beta Hydri Permit

Imperial Ships
   Location: Denton Paterus Controlled systems
   Discount: 10%
   Requirements: None

Discounts on Specific Outfitting

Weapons
   Location: Zachary Hudson Controlled systems
   Discount: 20%
   Requirements: None

Cargo racks and Hull Reinforcement (Does not apply to Bulkheads)
   Location: Edmund Mahon Controlled systems
   Discount: 20%
   Requirements: None

Information was taken from this thread at the official forums. These discounts (except those related to Powerplay) are subject to change, so this info might change. The forum thread seems to be updated regularly so information there should be pretty accurate.