I was contacted by Edfinity and they've created courses aligned with the 3rd edition of our book. Below is a blurb they sent me to share!
Edfinity is a modern, OER homework and testing platform backed by the NSF. I'm pleased to announce the availability of a comprehensive companion course for Precalculus by Stitz and Zeager: https://edfinity.com/products/5c96a916064244004ceb3903 You may also be interested in other homework courses in their growing catalog (edfinity.co/oertextbooks). General information about Edfinity and testimonials can be found at edfinity.com/homework
Highlights: No installation or self-hosting required. Algorithmic, randomized problems. Works seamlessly with WeBWorK. Remix, collaborate, and share across institutions.
Pricing. Edfinity is free for educators. Access is free for students until August 2019. Thereafter, it will cost $2-$4 per student per month, with subsidies for public institutions and departmental subscriptions. Edfinity is completely free for rural high schools and tribal community colleges.