This is the 10167th most frequent Russian word.
бесплатные
Free (without cost).
In this sentence, "бесплатные" is an adjective describing the noun "книги", indicating that the books are available at no cost. It represents a characteristics or attribute of the books provided.
Эта библиотека предлагает бесплатные книги для чтения.
This library offers free books for reading.
Here, "бесплатный" modifies the noun "вход" and describes that there was no charge for attending the concert. The adjective is used to characterize the condition under which access was granted.
Вход на концерт был бесплатный вчера.
Entry to the concert was free yesterday.
"Бесплатные" is used here to describe "образцы", showing that the samples given are distributed without any payment required from the customer.