I really would love to get my hands on textbooks for more advanced science and math, maybe even engineering. I want to learn as much as I can but my supplies now are diminishing fast. I also enjoy the text book format. With that being said where I can I get dirt cheap old textbooks? I mean really cheap - less than 5 dollars a book would be perferable.
I have looked online but mostly to no avail. Are there certain general places to find them? Like any sort of place that would typically throw them away?
Thanks in advance! I know there is probably no one answer to this and it probably all depends on luck but any advice would help!