This document provides an introduction to mobile campaigns on a budget for grassroots organizers. It discusses the unique aspects of mobile messaging such as ubiquity, interactivity, immediacy, and intimacy. It outlines the different types of mobile technologies including text messaging, mobile web, applications, and social media. It provides best practices for using text messaging and mobile websites effectively on a budget. Resources for low-cost SMS services, mobile website builders, and iPhone application development are recommended.