Actually, my goal is not to avoid withholding taxes. You only need to pay withholding taxes for the US audience, if you don't have a US account, so it basically means that all the non-US users will pay US withholding taxes starting from July, It's just a new breaking rule of Google AdSense for the US.
I didn't get this part. Non-US accounts have to pay withholding tax for the US audience? Or no withholding tax at all?
The cheapest UAE option would be at least $1500 or so per year. There's no US tax treaty, so I would expect that you'd have to pay 30% withholding tax at least on your US AdSense income?
So we're talking $1500 + 30% withholding tax, but a simple setup. Getting a UAE bank account can be a challenge and it can be a bit annoying to deal with freezones, banks and other companies in the UAE as customer service is usually not great and the rules can change frequently.
A UK company is very cheap and accounting should be quite cheap, too, if you only have few transactions. I would expect it to be even cheaper than the UAE setup. And no US withholding tax.
You could pay out a salary from the UK company, which would not be taxed in the UK, and it should qualify as foreign income in Thailand. Opening a bank account should be simple.
The only risk would be that you can't take a 100% salary due to transfer pricing restrictions. If you take a 90% salary (for example), then (if I'm not mistaken) you would have to pay 19% corporate income tax on the remaining profits, so 1.9% tax in total.
You would be able to reduce the corporate profits even more by claiming business expenses, such as flight tickets etc.
So, yes, there would be some accounting, but you wouldn't have to do that yourself and you might still come out ahead. And I would prefer dealing with UK accountants than customer service agents in the UAE.
If you use a US LLC (that would probably be the cheapest option) as a tax resident of Thailand, there might only be 15% US withholding taxes since there is tax treaty. But you should check with a Thai accountant if income from such a US LLC would count as foreign income since the LLC would be considered a disregarded entity by the IRS.
Actually, you should check the Thai rules for foreign income in any case. In theory, the Thai authorities could decide that even your UAE company should pay tax in Thailand. But that's probably rather unlikely, given that Thailand doesn't seem to care a lot about companies that are run by foreigners and have no local customers.
Finally, you could also consider a UK LLP, which - in terms of taxes - would be the UK equivalent of a (disregarded) US LLC. Some people in this forum have reported that they use a UK LLP to live tax free in Thailand. It would probably not be a correct setup, but you might get away with Google (incorrectly) recognizing it as a UK entity (=no withholding tax) as well as Thailand (incorrectly) recognizing it as foreign income (hybrid mismatch). The accounting requirements for a UK LLP should be even simpler than for a UK Ltd.
Oh, and if you're considering a UAE company, you should really also check traditional offshore jurisdictions like the BVI, Belize,
Seychelles etc. They should be even cheaper, but I don't know about bank accounts and if Google would pay out to an EMI account.
Please let us know what you find out, as I'm essentially looking for the same thing:
Cheap (relatively) anonymous company with limited liability for website
I'm expecting very low income for that project, so I'm looking for a really cheap option...
All in all, I don't think a UAE company is a bad choice, I would simply also consider other options.