One of the requirements of the Open Course Library project was that students could not spend more than $30 on materials. While I chose to use Spradley and McCurdy's Conformity and Conflict reader, there are a number of textbooks that are available online that meet this requirement (available on CourseSmart).
Eller, Jack David. 2009. Cultural Anthropology: Global Forces, Local Lives. New York: Routledge.
Ember, Carol R. and Melvin Ember. 2009. Human Culture: Highlights of Cultural Anthropology. Upper Saddle River, NJ: Pearson.
Haines, David W. 2005. Cultural Anthropology: Adaptations, Structures, Meanings. Upper Saddle River, NJ: Pearson.
Lavenda, Robert and Emily Schultz. 2010. Core Concepts in Cultural Anthropology, 4th edition. Boston: McGraw-Hill.
Nanda, Serena and Richard L. Warms. 2009. Culture Counts: A Precise Introduction to Cultural Anthropology. Belmont, CA: Cengage Learning/Wadsworth.
Podolefsky, Aaron, Peter Brown, and Scott Lacy. 2009. Appyling Cultural Anthropology: An Introductory Reader, 8th edition. Boston: McGraw Hill.
Robbins, Richard H. 2009. Cultural Anthropology: A Problem-Based Approach, 5th edition. Belmont, CA: Cengage Learning/Wadsworth.