Free K-12 textbooks. If I were a printer, I would give these folks a call.

About Us:
"Initially, CK-12 has commissioned a baseline archive of open educational resources (textbooks) through a combination of author donations, licensing partnerships, incentives for community-based authorship, and university collaborations. Flowing from this baseline, CK-12 will actively moderate the expansion of its content base from an active, contributing community while creating a framework for aligning its assets with an expanding base of learning standards like McREL Compendium. CK-12 intends to make use of the Creative Commons Attribution-Share Alike license, which grants freedom to anyone to use and reuse its core materials.

For print versions, the organization envisions working with a marketplace of on-demand presses to provide customized, but traditional looking, paper textbooks at low cost. This cost will be born by the user at their discretion directly at the on-demand press."