What is dime a dozen?

"Dime a dozen" is an idiomatic expression used in English to convey that something is very common, inexpensive, or easily obtainable. The phrase suggests that an item or situation is so commonplace that its value is perceived as low or negligible; essentially, it implies that there is an abundance of whatever is being referenced and that it's not particularly special or unique. The expression likely originates from the 19th century when certain goods were sold by the dozen for ten cents, emphasizing how affordable and plentiful they were.