Allows for expanded dialogue options when discussing business arrangements outside of the barter system. Especially applicable when speaking with Uncle Roe of Canterbury Commons, see Merchant Empire for details.
This perk only affect purchase. If you sell your items, the price is not affected by this perk.
If the 25% discounted price is below base price, the list price will be the base price.
Once you have attained this perk and the 60 Barter necessary for it, most vendors will already be selling you their items at the lowest cost (Base Value). And this perk doesn't increase the price you sell your items, although addional Barter skill do.