The situation with US citizens visiting Chile is this: when a Chilean wants to go to the US, he must apply for a US visa. There is no charge for the visa itself, but the processing of the application costs $45. Hence, Chile "retaliates", by charging US visitors the same 45 bucks. This is a one-time charge, good for the life of the passport. BTW, there are similar "reciprocity" charges for Canadian and Australian passport holders. Who says countries can't behave like children?