Dime a dozen

Idiom: "dime a dozen"  

Definition:

common and nothing special

Examples:

1) There are so many McDonalds that they are a dime a dozen these days.

2) Cheap computers are a dime a dozen.

中文解释： http://www.youzienglish.com/main/idiom_of_the_day/dime_a_dozen/cn/