law: Sale of Goods Act, 1930
  9. Ascertainment of price
  (1) The price in a contract of sale may be fixed by the contract
  
  or may be left to be fixed in manner thereby agreed or may be determined by the
  
  course of dealing between the parties.
  (2) Where the price is not determined in accordance with the
  
  foregoing provisions, the buyer shall pay the seller a reasonable price. What
  
  is a reasonable price is a question of fact dependent on the circumstances of
  
  each particular case.