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).
I got a brand new suit for 50 bucks—cheap at twice the price!
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!
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.
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.
Sunny: Ambert always uses hermes body wash!
Jack: Why'd you always make fun of him about this ! cheap shot!
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.