"To jew" is, sadly, a common way of saying "haggle" or "bargain" among some clueless/racist people. Usually it's in a negative sense (ie, "stop trying to jew me down" = "I don't like it that you're trying to haggle with me over this transaction"). My mother, OTOH, uses it when bragging about her successes at haggling with merchants, so it's not always negative in intended connotation. Sadly, repeated attempts to explain to my mother that it's an offensive turn of phrase have not been successful.