Barter (Fallout 3)

Barter is a skill in Fallout 3.

Description
The Barter skill is primarily used in the buying and selling of items, such as trading with a merchant or scavenger. In general, purchase prices will be lowered and selling price will be higher. It is the primary factor in price determination, and is also offset by the Barter skill of the non-player character in question. The skill is also used in certain dialogue options with non-player characters, where certain responses require Barter checks.

Math

 * Barter value
 * $$\text{Initial level}=2+(2\times\text{Charisma})+\left\lceil\frac{\text{Luck}}{2}\right\rceil$$

Example: A starting Charisma of 5 and Luck of 5.
 * $$2+(2\times5)+\left\lceil\frac{5}{2}\right\rceil=15$$


 * Derived values
 * $$Sale~Value~ = Item~Value~ \times \left ( 0.45 + \left ( \frac{Barter~Skill~}{100} \times 0.45\right ) \right ) \times Modifier$$


 * $$Buy~Value~ = Item~Value~ \times \left ( 1.55 - \left ( \frac{Barter~Skill~}{100} \times 0.45\right ) \right ) \times Modifier$$


 * The final value is rounded to the nearest integer at the end of the calculation.
 * The item value is the rated value of the item present in their Pip-Boy menu description.
 * The modifier is defaulted to 1 (or 100%), and it will change in accordance to other discounts or price increases coming from the specific vendor you're buying or selling from. For example, the 10% discount you get in Moriarty's Saloon for treating Gob kindly.

Each 5th point increase in score increases the sale price of an item by 2.25 percent. And a Barter skill of 11 allows the Lone Wanderer to sell at practically 50% of the rated value of an item.

A high Barter skill is a good choice for characters lacking Strength, since they do not have much room to carry many items and, subsequently, have less things to sell. However, having a companion partially negates this, since they can be given around 200 pounds of weight.

Available discounts

 * Master Trader - 25% discount with every trader in the game.
 * Craterside Supply - 30% discount upon receiving the Dream Crusher perk.
 * Moriarty's Saloon - 10% discount with Gob if he is treated nicely when initially meet.
 * Rivet City - 10% discount with all merchants in the city upon completing research into Rivet City's history.
 * Rivet City Supply - 10% discount depending on Lone Wanderer's choice during the quest Council Seat.
 * Potomac Attire - 10% discount depending on Wanderer's choice during the quest Council Seat.
 * Lock and Load - 20% discount upon completion of Economics of Violence.
 * Federalist Lounge - 10% or 50% discount by hacking the nearby terminal.

Interactions that require Barter skill
A number of dialog based trading can be altered with sufficient Barter:
 * 50 Barter is needed to obtain a 1,000 caps discount from the initial price of 2,000 when buying Charon's contract from Ahzrukhal during the unmarked quest Hired Help.
 * 50 Barter is needed to obtain a 500 caps rebate on the 1,000 caps price to buy Clover from Eulogy Jones in Paradise Falls.
 * 30, 50, or 70 are thresholds which, once crossed, can each provide a better level of reward in the unmarked quest Zip's Nuka Fix in Little Lamplight.
 * 75 Barter will give a much better bargain when trading cave fungus for strange meat during the unmarked quest Fungus Deal in Little Lamplight.
 * An unknown amount of Barter is required to obtain a better deal from Abraham Washington when selling Lincoln's artifacts during the unmarked quest Lincoln's Profit Margins.
 * 70 Barter is needed to obtain Sergeant RL-3 from Tinker Joe for 500 caps instead of 1,000.

Ways to increase Barter

 * Permanent
 * Leveling up (10+INT (+3 with Educated perk))
 * Bobblehead - Barter (+10)
 * Tales of a Junktown Jerky Vendor (+1 or +2 with Comprehension)
 * Scoundrel (+5 with each rank)
 * Tag! (+15)
 * Temporary
 * Ant queen pheromones (+2-6 depending on current Charisma, a perfect Charisma of 10 will not see any benefit)
 * Grape Mentats (+2-10 depending on current Charisma, a perfect Charisma of 10 will not see any benefit)
 * Button's wig (+5)
 * Roving trader outfit and hat (+5)

Notable Barter experts

 * Mister Burke (77) - Allistair Tenpenny's right-hand man, asks the Lone Wanderer to detonate the atomic bomb in Megaton.
 * Leroy Walker (68) - Leader of 6-man squad of slavers who have occupied the Lincoln Memorial.
 * Victoria Watts (63) - The Railroad member, asking your help in protecting escaped android Harkness.