'price-marker' is a modern English compound from the words 'price' + 'marker', where 'price' ultimately comes from Old French 'pris' (from Latin 'pretium') meaning 'value' or 'price', and 'marker' comes from Middle English 'mark(e)r'/'marken' meaning 'a sign' or 'to mark'.

'price' developed from Old French 'pris' (from Latin 'pretium') into Middle English 'price' and eventually modern English 'price'; 'marker' developed from Old English/Middle English roots related to 'mark' and the verbal sense 'to mark', forming the agent noun 'marker' in modern English, and together they formed the compound 'price-marker'.

Originally each element referred to 'price' (the amount asked/paid) and 'marker' (something that marks or indicates). Over time the compound kept the literal retail sense of a label showing price and additionally gained extended/business senses for entities that 'mark' or set prices.