GST valuation methods determine transaction value sequentially via comparative, computation and residual methods; special rules apply. Valuation under the draft GST Valuation Rules requires application of three primary methods in sequence: the comparative method, the computation method and the residual method to determine transaction value. Separate valuation approaches are specified for pure agents and money changers, and the draft contemplates future notification of specialised rules for insurers, air travel agents and lottery distributors or selling agents.