University earth science departments seeking to establish meaningful geoscience outreach programs often pursue large-scale, grant-funded programs. Although this type of outreach is highly successful, it is also extremely costly, and grant funding can be difficult to secure. Here, we present the Geoscience Education Outreach Program (GEOP), a small-scale, very affordable model tested for 5 y in the Department of Earth Sciences at the University of California, Riverside (UCR). GEOP provides in-class presentations for local K-8 classrooms; science, technology, engineering, and mathematics mentoring for middle and high school students; day-long events on the UCR campus for middle and high school students; and it allows UCR Department of Earth Sciences to participate in a wide range of community events. The program is managed by UCR graduate students, affects ~4,000 people (K-12 students, UCR students, the Riverside community at large) and operates for less than $3,000 U.S. annually. The GEOP model prioritizes simplicity, flexibility, and affordability to best meet the educational needs of Riverside County, California.