Council On State Taxation | 3,927 followers on LinkedIn. The Council On State Taxation (COST) is the premier state tax organization representing taxpayers. | The Council On State Taxation (COST) is a state tax organization representing business taxpayers, noted by one prominent tax policy expert as the “most influential nongovernmental organization in the state tax policy arena.” COST is a non-profit trade association based in Washington, D.C. consisting of nearly 600 multistate corporations engaged in interstate and international business. COST was formed in 1969 as the "Committee On State Taxation" by a handful of companies under the sponsorship of the Council of State Chambers of Commerce, an organization with which COST remains associated.