Abstract: The invention relates to a situation in which a merchant puts at a client's disposal an apparatus (9) for processing consumer articles (1) that are sold by him. The operation of the apparatus (9) is made dependent on the purchase of the consumer article (1) in question by making an element (4) releasing the operation of the apparatus (9) to form part of the packing (2) so as to make operation of the apparatus (9) only possible with the unlocking element (4).The unlocking element can take the form of a cardboard card (4) on which a magnetic strip (5) containing a code is applied. The apparatus may be a coffee making apparatus (9) comprising a device for reading the magnetic code of the card (4), releasing the coffee making process and for extinguishing the code.