Civilian stations trade one type of resource (Goons for Rez, Rez for goons, data for goons) for another depending on the system's type (Colony, Mining, Science). The exchange rate, however, can vary drastically from system to system. What factors influence these rates?
The barter rates are affected by your local faction reputation which you can confirm easily yourself by checking prices before and after a bribe and by the perks from your currently used specialists.
The Specialist perks which affect trading are:
Diplomat: Warpgate bribe discount
Slaver: Goon trade discount
Mediator: Relation improve discount
Negotiator: Blue print discount
Source: Specialist Skill tables