Altered Bargains is a technology that is unique to the Galactic Empire, and can be researched at the Spaceport in Tech Level 4. It costs 300 Food and 250 Nova, and removes the resource trading fee - in other words, the price for selling a resource at the Spaceport will be the same as the price for buying the resource.
Note that this will not let the player buy resources, then immediately sell them for the same price - when the player buys or sells resources, the price will change like normal. It just reduces the cost of buying, and increases the payment for selling.
"At Tech Level 4, the Galactic Empire has the ability to eliminate resource-trading fees completely using this Spaceport technology."