People have wanted to hire me to film for real estate, etc. but I have no idea what to do in order to make sure I can do that legally.

What do I need? A business license? Nothing? I can never get a straight answer.

Wyatt,

there are a number of resources on the FAA website about commercializing any UAS operation and what it takes to be certified.  At the very least in order to legally make money off of a UAS operation you need an exemption from FAA regulations allowing you to make money.  This is typically called a 333 exemption.  I would recommend starting there and doing a lot of research, I found a few examples and based my petition off of a successful example that I found.  It took me about 4 months to get mine and that was back at the beginning of the year when they only had a few to go through.  Beyond that you can set up a business or do it as a sole proprietor but that really just has to do with how you pay taxes for your income and expenses (consult tax professional!).  Good luck with your endeavors!

Brad