A dime a dozen

A dime a dozen: regular, comum, sem valor

“Rude people in New York City are a dime a dozen. Everywhere you go, there are rude people!”

“English teachers in Korea are a dime a dozen. There are so many English speakers here!”  (www.idiomeanings.com)

Plain-vanilla

Plain-vanilla: muito simples, sem nada de especial, comum, sem elaboração

“I want a plain-vanilla car without a lot of chrome trim.”

( www.dictionary.reference.com)