cheating neither old nor young (idiom); treating youngsters and old folk equally scrupulously; Our house offers sincere treatment to all and fair trade to old and young alike.
叟：老人。不欺骗小孩和老人。指待人诚实。多形容做生意讲信誉，买卖公平。
童：未成年的孩子；叟：年老的男人；欺：蒙骗。既不欺骗小孩也不欺骗老人。指买卖公平。
清·吴趼人《二十年目睹之怪现状》第五回：“但不知可有‘货真价实，童叟无欺’的字样没有？”