在英语中讨价还价可以使用以下表达：

Haggle：

用于非正式的讨价还价场合，如集市或跳蚤市场。

例句：In many countries, it's common to haggle over prices in the local markets.

Negotiate：

用于正式的商业谈判或大宗交易。

例句：We'd like to negotiate the price of the bulk order.

Drive a hard bargain：

表示在砍价时非常坚持和努力。

例句：I'm impressed that you got 50 yuan for that suit. You definitely drove a hard bargain.

Ask for a discount：

当购买数量多时，可以询问是否有折扣。

例句：Is there any discount on bulk purchases？

Try to rip me off：

表示怀疑价格不合理，想要避免被高价出售。

例句：Hey, don't try to rip me off. I know what this is worth.

Can you give me a little deal？：

询问是否可以得到一点优惠。

例句：Can you give me this for cheaper？

It's a bargain：

当价格合理时，表示满意。

例句：It's a bargain.

Lower the price a little？：

请求卖家降低一点价格。

例句：That's a bit expensive. Can you lower the price a little？

使用这些表达时，请根据具体情况和场合选择合适的词汇。