"tag or ticket affixed to something and indicating its price," 1878, from price (n.) + tag (n.).
Entries linking to price-tag
price n.
c. 1200, pris, "non-monetary value, worth; praise," later "recompense, prize, reward," also "sum or amount of money which a seller asks or obtains for goods in market" (mid-13c.), from Old French pris "price, value, wages, reward," also "honor, fame, praise, prize" (Modern French prix), from Late Latin precium, from Latin pretium "reward, prize, value, worth" (from PIE *pret-yo-, suffixed form of *pret-, extended form of root *per- (5) "to traffic in, to sell").
Praise, price, and prize began to diverge in Old French, with praise emerging in Middle English by early 14c. and prize, with the -z- spelling, evident by late 1500s. Having shed the extra Old French and Middle English senses, price again has the ancient sense of the Latin original. To set (or put) a price on someone, "offer a reward for capture" is from 1766.
tag n.1
"small, hanging piece from a garment," c. 1400, of uncertain origin but probably from a Scandinavian source (compare Norwegian tagg "point, prong, barb," Swedish tagg "prickle, thorn") and related to Middle Low German tagge "branch, twig, spike"), from Proto-Germanic *tag-. The sense development might be "point of metal at the end of a cord, string, etc.," hence "part hanging loose." Or perhaps ultimately from PIE *dek-, a root forming words referring to "fringe; horsetail; locks of hair" (see tail (n.1)).
Meaning "a label" is first recorded 1835; sense of "automobile license-plate" is recorded from 1935, originally underworld slang. Meaning "an epithet, popular designation" is recorded from 1961, hence slang verb meaning "write graffiti in public places" (1990).