This unit, designed for elementary school social studies classes, contains student materials and teacher's guide for exploring different means of exchanging goods and services. The unit is divided into two parts and designed around a learning center approach. In Part I the student uses pictures, games, and activity sheets to distinguish between goods and services, and learns about bartering. Students practice what they learn by bartering with one another. Part II deals with mediums of exchange other than bartering. Students make wampum and use it to buy goods and services in the classroom. In the final section of Part II the student analyzes why money is a good medium of exchange. The teacher's guide includes suggestions for taping the introduction and conclusion of each part, worksheets, and answer keys. Total time for the unit is approximately ten hours. (Author/KC)