Iowa Code § 904.310
The director may maintain a canteen at an institution under the director's jurisdiction for the sale to persons confined in or committed to the institution of items such as toilet articles, candy, tobacco products, notions, and other sundries, and may provide the necessary facilities, equipment, personnel, and merchandise for the canteen. The director shall specify the items to be sold in the canteen. The department may establish and maintain a permanent operating fund for each canteen. The fund shall consist of the receipts from the sale of commodities at the canteen and donations designated by inmates for reimbursement of victims' travel expenses. Any money in the fund over the amount needed to do normal business transactions, to reimburse any accounts which have subsidized the canteen fund, and to reimburse victims' travel expenses shall be considered profit. This money may remain in the institution's canteen fund and be used for any purchase which the superintendent or district director, as applicable, approves that will directly and collectively benefit the inmates of the institution or to reimburse victims' travel expenses.
Iowa Code § 904.310