Double taxes- home and abroad

You need a good US tax lawyer - any answer here is likely to result in punitive fines from state / federal authorities when they catch up with you

#18 given the way the US claims extraterritoriality rights over anything concerned with the US, I wouldn't be surprised if the US decides to tax the world because they use Starbucks

>>>You need a good US tax lawyer

Not really, that's overkill. I have my own business in the US and I can tell that you for these sorts of matters, you don't need a lawyer.

But you might need a decent US tax accountant who understands corporate returns (easy enough to find, but you won't find them at the tax preparation mills such as H&R Block, etc.) and, if you explore forming an offshore entity, you will definitely need a good accountant who understands issues related to the taxation of foreign entities (not so easy to find, but an otherwise decent accountant might have a referral to someone whom can provide that information.)

In any case, I would nonetheless create a business entity and have your client hire that entity, not you directly. Even if you create one domestically, you will gain the benefits of both liability protection and of having a separate business that become subject to its own set of tax write-offs, etc. (Perhaps you could use this as a springboard to finding additional clients.)

And you can easily form an LLC in the United States by yourself, without an attorney and with very little effort. (Nolo Press publishes an outstanding series of books that would help you to do this yourself, if you so choose.) In most states, the fees are reasonable and the paperwork required is minimal.