(a) The resale, by any person, of drugs acquired at preferentially low prices permitted under federal law only because of the Nonprofit Institutions Act (15 U.S.C. Sec. 13c) is prohibited except in any of the following instances:

1. (1) When for the person’s own use, as defined by the federal courts in Abbott Labs. v. Portland Retail Druggists (425 U.S. 1, 47 L. Ed. 2d 537) and DeModena v. Kaiser Foundation Health Plan, Inc. (743 F. 2d 1388).
2. (2) When sold to a purchaser also eligible for those prices under the Nonprofit Institutions Act, that controls, is controlled by, or is under common control with, the seller, and that purchases the products for its own use, as defined in paragraph (1).
3. (3) When sold to a walk-in customer pursuant to a prescription, provided that those sales represent less than 1 percent of the drugs purchased by the seller for its own use in this state.