Supply between related persons: loans with only interest are exempt from GST, while separate processing fees remain taxable. Supply between related persons is treated as a supply even without consideration; services of extending loans are exempt from GST when consideration is only interest or discount. Distinct charges such as processing or administrative fees constitute taxable consideration for loan processing/facilitation services and attract GST. Where related parties charge no such fees beyond interest/discount, there is no taxable service and open market valuation should not be applied.