Since there are so few these euphs on the market, I was wondering if anyone had any idea of what a used one is worth. Maybe the ratio of value as compared to a Yamaha 642 all things being equal. A friend and I are trying to arrange a barter deal (new jinbao tuba to Yamaha 621) he thinks a Yamaha 642 and a 621 are a wash when it comes to value on the market. We are good enough friends to handle any answers.