You’ll have to decide for yourself when to “formalize” your company by creating a legal structure like an LLC, buying liability insurance, and such. For advice on these matters, you can meet with volunteers at SCORE, and there are even places to get inexpensive legal help. Meanwhile, why not pull out a $100 bill and take a look at what you can do with it.
Often, what happens is that we run into unscrupulous Internet Marketers (IMs) who have less-than altruistic intentions of extracting money from you rather than helping you to make it. However, this isn't something new. People have been falling for networking marketing, pyramid schemes, and affiliate marketing scams since before the start of the net.