mass-market paperback

a small-sized paperback book that is sold in large quantities in many different retail outlets

A mass-market paperback is a type of book that is produced in large quantities and sold at a lower price compared to other formats. It has a flexible, paper cover and is usually smaller in size. Mass-market paperbacks are designed to be affordable and widely available, often found in bookstores, supermarkets, and airports. They are popular for their portability and cost-effectiveness, making them a common choice for bestsellers and popular fiction.