> in Europe it costs money to start a business, some paperwork and taxes is involved, even if you don’t make a single sale

not everywhere - in Poland it is fine to run a tiny-scale business without registration

https://www.biznes.gov.pl/pl/portal/00115 - among requirements, scale must be less than 75% of a minimum wage. Enough to test it.

> otherwise how do people know you are a legit business? For example, I’m not giving my credit card details to any random website to buy silly stuff unless they are properly identified

I do not care so much, as long of amounts are tiny - in case of fraud it is bank's problem