Is it permissible or forbidden for a tourist to buy a product for many times its original price, exploiting his ignorance of the price, and then for the friend to take his share from the shop owner?

For the work of a foreign tour guide to be permissible, it is stipulated that their work must be in a permissible field. It is not permissible for the guide to collude with the shop owner to inflate the price of a product in order to take a share of it, as this involves deception and fraud to unjustly seize the tourist's money.