Forum Moderators: LifeinAsia
Whether you need a business license is a local issue and has no relation to how much money you're making, but you might not really mean "business license" -- a lot of people use that term inaccurately to mean the formation of a separate business entity such as a corporation or LLC, instead of operating as a sole proprietorship. But there is no limit on the amount of money you can make as a sole proprietor, so there'd be no legal requirement that you do so. There may or may not be tax advantages, but that depends very much on your personal situation and that is certainly a topic about which it would be worth consulting an accountant.
A good online source for this kind of information is nolo.com.
Also, you can hire a CPA or go to near by H&R Block or generally you should be able to find free tax help at near by library or college or walmart by tax volunteers.
>Do I need to start paying quarterly taxes?
Yup
>Should I just hire a CPA and let them figure all this out?
Absolutely. When you get to that level of income, you want pro help. Plus, you want somebody on your side that knows the game if you get audited.