9.2.1. No person may purchase tobacco at retail in Québec for a price that is lower than the aggregate, in respect of the tobacco, of the excise duty applicable under the Excise Act, 2001 (Statutes of Canada, 2002, chapter 22), the tobacco tax applicable under this Act and the tax applicable under Part IX of the Excise Tax Act (Revised Statutes of Canada, 1985, chapter E-15) computed on the aggregate of the excise duty and the tobacco tax.