S.D. Codified Laws § 50-12-8
Upon application in writing on a form furnished by the department and the payment of a fee of one hundred dollars for each aircraft to be so used, the department shall furnish a dealer with a commercial use stamp upon which is printed the federal aircraft registration number (N, X, etc.). The stamp shall be affixed to the aircraft dealer's certificate as directed by the department. The stamp authorizes the aircraft to be used for aviation commercial purposes, but not for spraying, dusting, fertilizing, seeding, or defoliating. Use of the aircraft for prohibited purposes is a Class 2 misdemeanor.
The commercial use stamp shall expire twenty-four months following its issuance or at the expiration of the dealer certificate to which it is affixed, whichever occurs first.
SDCL 50-12-8