law: Sale of Goods Act, 1930
  5. Contract of sale how made
  (1) A contract of sale is made by an offer to buy or sell goods
  
  for a price and the acceptance of such offer. The contract may provide for the
  
  immediate delivery of the goods or immediate payment of the price of both, or
  
  for the delivery or payment by installments, or that the delivery or payment or
  
  both shall be postponed.
  (2) Subject to the provisions of any law for the time being in
  
  force, a contract of sale may be made in writing or by word of mouth, or partly
  
  in writing and partly by word of mouth or may be implied from the conduct of
  
  the parties.