If you visit Sweden, don't buy ice cream in the historic area of Stockholm ("gamla stan").
As an American you might think "$10 for a single scoop of vanilla, that's nothing. A minimum wage worker packing groceries earn twice that in an hour back home". But you are not helping a starving ice cream labourer with your purchase, you are simply being taken for a ride. Walk a couple of blocks more and check the signs, and you can buy it at half price from a respectable establishment instead. Most likely the ice cream will be better at the next place as well.