"漫不经心地看商品" can be translated into English as "casually browse through the merchandise" or "look at the goods in a casual manner".
Here, "casually" conveys the sense of doing something without much effort or attention, while "browse through" or "look at... in a casual manner" indicates the act of examining items without a specific purpose or intense focus. Both expressions capture the idea of looking at goods in a relaxed and unhurried way.