You can get all the info you need for free.
This will cost you time. There are also some free guides and some are very good. Personally, I'd say: Don't waste time on levelling guides. Or any other guides. I get curious all the time, but mainly you get the information that is posted on the forums / fan sites, pressed into a double-line-spacing pdf. And that's it.
If that's worth the money... well, you decide.