These are specifics and probably not interesting to the rest of HN.
BUT, you can open a sole proprietorship, fill out some forms, and voila: you pay 4% taxes. After all the healthcare and stuff, you end up with 1068 euro net on a $20k (17k eur) yearly revenue.
At $48k/year, you get 3040 euro/month net. Now you're getting paid almost as much as the president. Your taxes will go up a bit next year, so save up, but for the first year you have plenty of extra money in the bank that you can leverage for making even more money.
And if you target San Francisco, you're competing with people who are asking for $130k+/year.
That is REALLY interesting! Quite a useful and nice way to work with tax. What does the percentage increase to in the following year?
It is a shame that the UK does not have anything like this. The best you can hope for is to contract and that give an average tax of around 26% to 30% depending on how creative your bookkeeper is.
Germany as my alternative example is quite a different story, there being freelance is very difficult due to the cost of healthcare that you HAVE to pay and their tax law is extremely complicated, you pay loads more tax than the UK for example. I know some friends who too permanent employment in Germany as it was more beneficial than being freelance.
Invoicing 1500 eur/month as a company, minus operation costs, minus taxes, gives 800-850 eur/month, which is barely livable. Lawful minimum is about 750 eur.
Swizec is right, there are ways to incorporate to pay less tax, but not everyone can go that way.
Rent and utilities in Ljubljana cost us about 800 eur. What is left is maybe enough for one person, who will never own any property.
$20k/y is close to a welfare level in Slovenia, except maybe in countryside.