The paper considers a particular case of onomastic motivation, providing examples of the use of the adjective tani "cheap" in the creation of pharmacy names in Poland (e.g. Tanie Leki "cheap medicines", Tania Apteka "cheap pharmacy"). This Polish word is frequently used in marketing, both as an element of company names and marketing slogans. In many instances tani constitutes part of a complex pharmacy name, e.g.: Całotygodniowa Apteka Familijna - Tylko Tanie Leki, Super Tania Apteka im. Zawiszy Czarnego, Centrum Tanich Leków - Apteka św. Barbary. On the basis of judgments from Polish administrative courts, the article discusses the question of the distinction or lack of one between advertisements and proper names. The significant fact is that the Pharmaceutical Law has prohibited the advertising of the operations of pharmacies since 2012 and, as a result, the use of names with the component tani was found to be in violation of the provision. In response to this, the owners of stores have argued that the proper name refers to the object alone, having no literal meaning. The controversial phrases were used to create legal names which are placed on signboards and in announcements. The paper focuses on a more general problem: chrematonyms and appellative lexis can hardly be distinguished due to their persuasive and marketing value.