In Spain you have to pay €250 a month Autonomo, a social tax, even as a sole trader/freelancer. €250 x 12 months is €3000 (roughly $4000). This is a lot of money to get taxed for nothing annually in a country where minimum monthly wage is in the region of €550 and rent prices are high. Ever been to Barcelona and wondered why it wasn't the design Mecca it had all the makings of? The fantastic design scene seen in the design of posters, flyers, logos, shops, interiors, all the design festivals, the conferences… yet nothing significant comes out of it. The social tax prevents small business there from starting up, a policy that makes room for large companies.
In Poland, it costs a similar amount of social tax (ZUS) just to stay registered as a company (a sole trader that is, there are higher costs associated with keeping a proper company registered).
It's better in the UK and Republic of Ireland:
In the UK the minimum amount of social tax (NIC) for a sole trader with minimal or no income is £2 per week, which seems fair enough.
In Ireland the social tax (PRSI) is 3-5% of your income but no less than about €250 per year (might have gone up this year). Seems bearable as well.
In both countries (not 100% sure about UK) you can register a Business Name (€20 in Ireland) without having registered a company. In Ireland you can start trading without even registering with the Revenue until you make around €3500.