1.cheap at twice the price 形容某个东西很便宜！！
Remarkably or exceedingly inexpensive (as in, even if you doubled the price, it would still be a good value).
好便宜！就算这个价格乘以二，也还是很便宜！白捡一样！
I got a brand new suit for 50 bucks—cheap at twice the price!
我买了个西装才50刀？太便宜了吧！

2.cheap Charlie 小气鬼！
A derogatory term for a miserly or parsimonious person. Used largely in countries of Southeast Asia, it likely originated in Vietnam during the Vietnam War to refer to American GIs (who called soldiers of the Viet Cong "Charlie") unwilling to spend extravagantly at bars, restaurants, or for prostitute.（用英语来解释英文）
Buy us a round of drinks, don't be a cheap Charlie!
诶诶诶请我们喝酒啊！别当小气鬼咯！

3.dirt cheap 很便宜！这里的dirt相当于super，超级便宜的意思。是一个年轻人比较爱用的表达。
I found the shoes yesterday, they were dirt cheap, i had to buy them.
我昨天看上几双鞋，我的妈呀好便宜！不买不行！不买对不住自己！

4.一元店：Dollar Tree（美式）, Poundland（英式）

5.cheap shot 恶意中伤，不公正的批评。也就是“黑”某人A mean or unfair criticism.
I didn't appreciate that cheap shot you took at me at the party. You made me look foolish in front of our friends.
你昨晚在爬梯上那样黑我我真的很不爽，真的是让我在一群朋友面前出丑！
Sunny: Ambert always uses hermes body wash!
安姆博特老是用爱马仕的沐浴露诶！
Jack: Why'd you always make fun of him about this ! cheap shot!
你这么老这么黑他！真的要不得！
（此处Sunny要给安姆博特说对不起，NO OFFENSE）

6.all over someone like a cheap suit 形容某人很粘人，挂人身上不下来那种。
pawing and clinging; seductive. (A cheap suit might cling to its wearer.)
She must have liked him. She was all over him like a cheap suit.
她一定很喜欢他吧，总是挂在他身上像个cheap suit