Hey guys; can anyone recommend some tough textbooks for math and science high school and calculus level. Not the 100$ new ones but some old ones such as some listed in the "So you want to be a mathematcian" thread? Thanks.
Google is your friend, there are ton's of free textbook pdf's/online videos/courses out there.
If you really prefer text and not the computer screen though (some do), older editions of textbooks can be had for fewer than 10 dollars if you do enough searching. Fundamental’s of Physics is a good resource for physics, and older beat up editions I've seen selling for about 5 dollars. (Plus shipping of course.)
Maybe it's a little too advanced, but since it's self study(I'm assuming here), there is no deadline or rush to understand the material.