"While open educational resources (OERs) are a fantastic well of lesson plans and materials that can benefit teachers and students alike, there remains a troublesome question about their use in schools – who exactly is vetting the information presented by these resources? Because standards for open educational resources often do not align with the standards of school districts, state educational departments and the like, there is often dissonance between the information available and the information that will actually be useful for a school’s curriculum."
While free is always nice, quality is more important.