bargain（与某人就某事）讨价还价，商讨条件
He said he wasn't prepared to bargain.
他说他不愿讨价还价。

haggle over（尤指）讲价
My mom was haggling over the price of a shirt.
我妈为一件衬衫在讨价还价呢。
I hate having to haggle over prices.
我不喜欢讨价还价。

I am on a tight budget so I am looking for your best price.
我预算紧张，所以我要你给个最低价。
I don't have a lot of wriggle room.
我的预算没有太多活动空间。
How far can you come down in price to meet me?
你的价格还能降多少？

Is there any discount?
有折扣吗？
Can I get a discount?
能打折吗？
Can you lower the price?
价格你低一点吗？
Can you make it lower?
你能降点价吗？
Is that the best you can do?
这是你的最大折扣吗？
How much is this and this altogether?
这两个一起多少钱？