scalper
noun [ C ] US informal uk/ˈskæl.pər/ us/ˈskæl.pɚ/ (UK tout)
倒卖（戏票等）的人
someone who buys things, such as theatre tickets, at the usual prices and then sells them, when they are difficult to get, at much higher prices
A scalper offered me a $20 ticket for the concert for $90. 有个黄牛可以卖给我一张音乐会的票，票值为20美元，他要价90美元。