A lot of options here.
-Estonia is an interesting choice since they also offer e-residency which can come with other perks and totally opens EU market for you, you receive their government ID. Estonian government services are fully digitized so you should not expect many bureaucratic headaches.
-UK is pretty easy and quick, you can have company up and running within days. There is a non-resident option and it's not really expensive. The actual formation costs £10 but you will need UK address, so with that service, you can get a company formations company to do it for you for £150 or less.
You will have to file accounts in about 18 months since forming, and of course, you will need to get an accountant to help you with that, and with lowering taxes and all other expenses. You don't need to be in VAT system until (I think) £85k threshold.
-US will be more expensive and a bit longer process, but best if you're targeting US market. I have no idea how taxing or accounting works in the US.
-Almost all (if not all) EU countries offer non-resident company formation option. Holland, Germany, Romania are good options (again, depending on the target market and your connections with the country).
-Ireland is tax haven and you shouldn't pay any corporate tax for the first 3 years.
Please don't rely solely on the info I (or anyone else) said here. You should consult with qualified people and do your research.
