Origins
The English word 'price' descends from Old French 'pris' (price, value, reward, prize), from Latin 'pretium' (price, value, worth, reward). The Latin word traces to the PIE root *per- (to traffic in, to sell), though the exact pathway is debated among historical linguists. What is not debated is the extraordinary productivity of 'pretium' in English — it generated an entire family of words spanning commerce, aesthetics, and emotion.
The most striking fact about the history of 'price' in English is that it was once the same word as 'praise.' Old French 'pris' carried both meanings: the monetary value of a thing and the verbal act of declaring something valuable. When 'pris' entered Middle English, both senses came with it. A single word meant both 'what something costs' and 'what something is worth in the estimation of others.' Only gradually, during the fourteenth and fifteenth centuries, did the two senses diverge into separate spellings — 'price' for the monetary sense and 'praise' for the evaluative sense. The split is purely orthographic; etymologically, they remain the same word.
The Latin source 'pretium' generated a large family in English, all united by the idea of assigning value. 'Precious' (from Latin 'pretiōsus') means 'of great price.' 'Appreciate' (from Late Latin 'appretiāre') means 'to set a price on,' hence 'to recognize the value of' — and in financial contexts, 'to increase in value.' Its antonym 'depreciate' (from Latin 'dē-' + 'pretium') means 'to reduce in price.' 'Appraise' means 'to set a price on,' a professional valuation. 'Prize' (a reward) is a doublet of 'price,' entering English through a slightly different French form.
Latin Roots
The semantic range of 'pretium' in Latin was already broad. It meant the monetary price of goods, the ransom paid for a captive, the reward for a deed, and the value or worth of a person or thing in the abstract. Cicero used 'pretium' in philosophical discussions about moral worth; Virgil used it for the rewards of heroism. The word carried no inherent distinction between monetary and moral value — a distinction that modern English enforces through its separate vocabulary of 'price' (monetary), 'value' (broader), and 'worth' (moral/personal).
The history of the word 'price' in economic thought is itself significant. The medieval 'just price' (Latin 'justum pretium') was a central concept in scholastic economics: the idea that every commodity has a morally correct price determined by custom, labor, and social need, and that charging more was sinful. This concept, developed by Thomas Aquinas and other theologians, governed European economic thinking for centuries. The modern concept of price as determined by supply and demand — the 'market price' — emerged during the seventeenth and eighteenth centuries as a conscious departure from the just-price tradition.
The PIE root *per- that underlies 'pretium' may also be the ancestor of Sanskrit 'pari-kray' (to sell) and Greek 'peráō' (to carry across for sale), suggesting that the concept of 'selling' was linguistically connected to 'carrying across' or 'transferring' — commerce as the movement of goods from one person to another.