It is unlawful for any merchant to advertise or offer for sale any item of merchandise with a limitation upon the number of the item that any retail purchaser may purchase at the advertised price. It is further unlawful for any merchant offering or advertising any item of merchandise in his place of business at any given price to refuse to sell to any prospective retail purchaser for cash the whole or any part of his stock of such item at such price. However, this section shall not be applicable to a purchaser purchasing for resale.