I have been self-employed under a Polish business (
działalność gospodarcza) for the last few years. With income tax plus mandatory pension and health contributions, over a third of my income goes to taxes or other mandatory fees (like the requirement to have a licensed accountant keep your books). It really isn’t much different than most other EU countries. And of course one pays a comparable VAT on shopping.
Often in Poland people say “Why are you running your business here? Base it in Czech Republic!” The grass always is greener on the other side.