(a) Except as provided by Subsection (b) of this section, a retail store that is owned or operated by an institution of higher education may not enter into a transaction for the sale or lease of goods or services in which the institution extends the credit of the state to the obligor.
(b) This section does not apply to an extension of credit to a student for the purchase of books or other educational supplies if the credit may be offset against undistributed grant or loan funds that are held by the institution for the student or that the institution is entitled to receive on behalf of the student. The institution may not withhold grant or loan funds to require the student to purchase books or educational supplies from a store that it owns or operates.