I used to be able to for example pull up sample tests in math and science that teachers and volunteers had just put up on the web for free. Formula sheets. Periodic tables. Diagrams.
Now, a bunch of people have put up the same material and then put them behind paywalls, sometimes worst material, and they've finagled some deal with Google or search engine optimized their web pages in some way that I can't find the high quality free stuff.
For-profit industries kill voluntary and charitable organizations and often don't do things better.