Customs fees in Europe

Hello, have you ever paid customs fees for giveaways if you live in Eu? Yesterday I got my first box because I won the Skin1004's giveaway, and Ups charged me for about 10 euros. Strange thing they did not let me know before (I received an email when I purchased something outside Eu before) , the courier just rang my bell and had this notice. Should I expect customs fees for every giveaway I won and do you know if they are affordable fees like this time or I can get a heartattack due to higher fees without previous communication? 😅