Open Educational Resources (OERs) are freely accessible, usually open-licensed software, apps, or media that are useful for teaching and learning purposes. Most technology-related OERs have a level of the service available at no cost but might charge for additional features or broader use. Below are examples that you might want to check out!
Share My Lesson - offers user-rated Common Core exemplar lessons in their library of more than 250,000 resources.
LearnZillion - like the Khan Academy of Common Core, with thousands of lessons tied to the standards.