Ok, here is a quick post about how awesome the internet is.
Universities are putting videos, audio, and written materials from their courses online for free. It is staggering the amount of information that is publicly available. You can dabble in essentially any subject you want and pick up a pretty damn good introduction to that subject.
For example, you could listen to lectures on early modern German history. Or maybe brush up on your early modern English history. The reference material available can inform your game world in so many ways.
Why are you still buying splatbooks?