Editors' Note: Registration costs $39.95.
From the developer: "The Boson Linux practice tests will prepare you for the actual Linux exam. This includes practice tests for the Red Hat Certfied Expert (RHCE) exam. Each practice exam contains over 200 questions and explanations and has a money-back guarantee.
"Each test in this download allows unlimited use of a 12-question database. Registration gives you use of 200+ questions, answers, explanations, and use of flash-card mode."