European law is unfortunately very unfriendly to small businesses. For example, sending a correct invoice is a requirement, and you have to store them for at least 5 years. That can be done only if you have set up a corporation or self-employment and have obtained all the necessary identification numbers. Fortunately Stripe made things much easier, but still - beginning to process cards is lengthy. Paypal in Europe takes a very big commision and they will block your account and ask for the same lengthy card processing process after you make few thousands in sales. Taxes are hard to file yourself even if you do only local sales, and becomes impossible to manage yourself once you sell out of EU.