This study investigates how instructors consider resource cost and availability when compiling assignments in their course syllabi. It uses the academic planning model from Lattuca and Stark to frame the influences on instructional material selection. It employs a critical incident technique method, asking instructors to take into account one course syllabus when making assignments. Findings address differences across formats including books, chapters, articles, and video. Findings show differences between disciplines and concerning lack of familiarity with fair use. It concludes that increased consultation with library personnel regarding course books would help provide students with affordable materials in compliance with fair use.