Now textbooks aren't all bad. They are a good source of information from time to time and are a good resource. But as we move our students online and to a a hybrid 1:1 environment, we want to offer our students a way to learn in the way that is best for them - not for the teacher.
So that is why I like CK-12 as a resource. It is best for math and the sciences as those subjects offer the complete suite of learning. For example, if you go here you can see that the student learning about angles can read a short description about angles, then, if necessary, watch a video; practice problems and then there is an interactive way to challenge the student. So for me this is great. If the student gets it after reading the text, then s/he is done. If a video is all that is needed or is better than the text then the kid can stop there. If the student wants practice then there are two ways to go about it. Find a textbook that offers all of that AND IS FREE!
Finally all the learning can be done on one's smartphone as well.