It is unlawful for any person engaged in commerce to pay, grant, receive or accept anything of value as a commission, brokerage or other compensation, or any allowance or discount in lieu thereof, except for services rendered in connection with the sale or purchase of goods, wares or merchandise. It is unlawful for either party to the transaction to pay or grant anything of value as a commission, brokerage or other compensation, or any allowance or discount to the other party to the transaction or to any agent, representative or other intermediary acting for, on behalf of or subject to direct or indirect control of the other party to the transaction.