Latin, literally "let the
buyer beware." By todays standards it serves as a warning (caveat is a warning) to customers who are cautioned to be ever on the guard for misguided salesmen who decide not to live up to their end of a bargain.
Emptor is from
emere meaning to purchase. It's become axiomatic as a principle in commerce that the buyer is on his own and responsible for assessing the quality of a purchase before buying. The opposite slogan is
caveat venditor. A warning, as well as a consumer rights expression that means "
let the seller beware."
The phrase arose in England in 1523. It's about the same as saying "don't buy a pig in a poke
Sources:
etymology:
www.geocities.com/etymonline/
Latin Language:
http://www.aboutlatinlanguage.com/