The physical books can be had on secondhand bookstores for significantly less, albeit they're still sold for more than they aught to be, usually. Thriftbooks is an online reseller that has them for around $25 USD but local thrift stores and library book sales have them sometimes and will sell them for next to nothing.
There are some inexpensive/free programs/websites that exist to automate and simplify basically everything in the game. IME the only advantages the manuals have over the apps is that the manuals convey the bigger picture of how the game works.