Master Trader/Fallout 2

Master Trader is a perk in Fallout 2.

Effect
Adds a -25% discount to purchased items. The actual discount varies between 15 and 30%, as the game appears to apply the cumulatively, rather than sequentially. The Fallout 2 manual incorrectly states that this perk makes the player's own items more valuable, and that the Barter requirement is 60%.

Fallout 2: Due to a change in the barter formula, this perk now subtracts 25 points from a barter modifier, which is then multiplied by the original price and the Barter skill modifier.

By default the modifier starts at 100%, but Reaction modifiers can add 25 points, 0 points, or subtract 15 points at the same time, making the discount appear to vary from 20% (when there is a +25 point "negative reaction" modifier), to 25% (with "neutral reaction" modifier (0 points), up to 40% (with a -15 point "positive reaction" modifier).

Either way, the perk is functionally useless, as there is no shortage of money in the games, although the Fallout 2 barter system makes it necessary to have this perk if the player wants to make a profit at a reasonable barter skill (around 110%) AND have a positive reaction modifier, for some low level merchants.