What is one primary characteristic of duty-free sales?

Duty-free sales are characterized primarily by their exemption from excise duty, which is a tax imposed on specific goods. This exemption allows consumers to purchase goods without the additional cost that would typically be added due to such taxes. This arrangement is commonly utilized at international airports or border crossings, where travelers can buy items without excise duties because they are intended for personal use outside the country of sale. The option indicating that duty-free sales are exempt from excise duty correctly highlights this key feature, as it is the basis for why these items can be offered at lower prices compared to standard retail sales. Items sold duty-free generally include alcohol, tobacco, and perfumes, and this practice is regulated and limited to specific conditions to prevent abuse.