If you experience odd or unexplained amounts of merchant gold, even after the merchant has restocked, then you probably have another mod loaded after Trade & Barter which has altered the VenderGold leveled lists. To resolve the issue either: 1) Change the load order, and make sure that Trade & Barter loads after the other mod, or 2) Click the "Disable Merchant Gold Options" option from the menu. This will reset the Merchant Gold options and allow the changes from the other mod to prevail without further interference from Trade & Barter.
By default this option is turned off. When you load the mod menu, the value you see displayed is the setting currently in use in your game. The vanilla value is 2.0, so any other number indicates that another mod is already changing this setting. If you decide to turn this option on, than the settings from Trade & Barter will overwrite any changes to this value made by other mods. If at any time you wish to revert the settings back to those made by another mod, simply toggle off this option and reload your game. You will need to reload your game before the changes from Trade & Barter are fully canceled out.