The paper demonstrates how school districts can have a low cost software library for instruction by utilizing public domain software. Such software can be used to augment the curriculum and to meet the individual needs of special education students. Specific examples of how one school district has used public domain software in computer-assisted instruction are described. An introductory section explains what public domain and user supported software are. Selection criteria are offered to aid in the selection of software for classroom uses or for a specific student. Applications in specific curricular areas are considered including examples of how such software has been integrated into science, mathematics, social studies, reading, language arts, problem solving, and fine arts curricular areas. Finally, examples of the use of public domain software in instructional support are given including instructional management, electronic bulletin boards, word processing, and programming. Specific sections cover such topics as: "Copying Apple Public Domain Disks"; "Getting Apple Public Domain Software to Run"; "Getting IBM Public Domain Software to Work"; "Public Domain Vendors"; and "Computer Resources for Teachers." Also included is the script for a slide show presentation. (DB)