bargain是动词，cheap是形容词
cheap adj. 便宜的，廉价的
普通用词，可指物美价廉的，也可指价格便宜但质量低劣的。
例句:
Her hat looks cheap.她的帽子看上去很便宜。
He bought a cheap mountain bike.他买了辆便宜的山地自行车。
bargain v. 讨价还价，谈判，商谈条件
主要用于商贸领域，指买卖双方为了达成协议而在价格等方面进行商谈。
例句:
She bargained with him for the new cosmetics.她为了那些新化妆品和他讨价还价。
The workers bargained a new wage increase.工人们谈判再一次提高工资的条件。
They bargained for an improved working environment.他们提出改善工作环境的要求。
You are likely to get a better deal if you are prepared to bargain.如果你愿意谈判，你很有可能得到更好的待遇。
Unions bargain with employers for better rates of pay almost every year.为了争取更高的薪酬，工会几乎每年都要与资方进行谈判。
