The document provides guidance on conducting low-cost usability testing for mobile applications. It recommends testing with 5 participants to find most usability bugs. The testing process involves preparing test scenarios and devices, introducing participants, observing and recording their comments and interactions, summarizing findings to identify and rank issues, and addressing them. While low-cost, some challenges are finding representative participants and testing entire user journeys. The estimated cost for a sample test with 3 participants is 29 person-hours.