If you adopt a free textbook but would like the ease of a free or low-cost ancillary provider, there are several options available, below. Ancillaries offer time-saving features, including auto-grading. While some of these ancillary resources are free, others range from $10-25 per student.
Many low cost third-party providers, like Lumen Learning, work as direct bills to the enrolled students: instructors list the resource information on their syllabi for students. Students subscribe individually and receive access to course materials after payment. While not comparable to OER's barrier-free model, these can still significantly reduce the cost of learning materials, resulting in a total course learning materials fee of $25 for a class that previously had a $300 textbook.