All addon (and game) settings are stored in your 'World of Warcraft/WTF/' folder. Specifically, each module of TradeSkillMaster stores its settings in a file within the 'World of Warcraft/WTF/Account/ACCNAME/SavedVariables/' folder with the file being a .lua file with the same name as the module. Be sure you have WoW completely closed before messing with these files or else your changes may not have any effect.