When you say something is as cheap as chips you mean it's very cheap.
如果你说某些东西“ cheap as chips ” 就是说，这些东西非常便宜。
Examples:
例句：
People keep asking my mother which designer created her beautiful party dress. In fact she bought it at a street market. It was as cheap as chips.
有人总是问我妈妈，是哪个设计师为她设计的这条漂亮的派对礼服。事实上，我妈妈是在街市上买的，价格非常便宜。
Mobile phones used to be very expensive. Today they are as cheap as chips.
手机以前很贵，但是现在非常便宜。
