"做旧货生意的" can be translated into English as "someone who deals in second-hand goods" or "a second-hand goods dealer".
Here are some example sentences for context:
1、 He is someone who deals in second-hand goods, often finding valuable items at low prices.
(他是个做旧货生意的,经常能低价淘到好东西。)
2、 As a second-hand goods dealer, she has a keen eye for identifying valuable antiques.
(作为一名做旧货生意的,她对识别有价值的古董有着敏锐的眼光。)