Offer your thoughts or opinion on the input financial query or topic using your financial background.

I'm 18. How to build good monthly income at my 20's?
Market rate of return averages about 8% annually (sometimes more, sometimes less or negative). To get 30k monthly -- even taking that as pretax -- you're talking about 360k yearly. Divide that by 0.08 and you need to have savings of 4.5 million--- and really you should double that for safety..  Tl;dr: forget it. Added thought: If you really have $20k/month coming in, you really have no business asking the Internet for advice. Hire a professional financial advisor (not a broker, someone who is paid a flat fee for their expertise and has no incentives to give you less-than-optimal advice). . The money they will save/make for you will more than pay for their hire.