I will second what record.play.rewind said. I took the Part 107 test a few days ago and passed it after self-study, using the Rupprecht Law site and the references he provides. It's an excellent resource. And when record.play.rewind (sorry, I don't know your actual name) says "CHART CHART CHART", he's not kidding. Interpreting sectional charts is a big part of the test AND one of the primary resources you'll use when you're going to fly in a new area.
On a related note, one of the things I realized after studying for the Part 107 test, researching drone laws in the states I'll be flying, and reading through a lot of forum and blog posts, was that passing the 107 cert exam itself means squat, really. It just allows you to fly as a non-hobbyist. Practically, I think it's going to take me a few months of preparation, further research and planning, and tons of practice before I'm going to be at a point where I will even think about offering services commercially to the general public. So, my additional advice as a complete rookie at this, I admit, is not to jump headfirst into printing business cards and cold-calling potential clients the day after you get your 107 certificate
What I've learned so far shows me how little I know!