Sometimes admission tickets are quite cheap. For example, going to Disneyland or Universal Studios International, a ticket costs more than 600 to over 1,000 dollars. It seems expensive, but in reality, it's actually very cheap.
Because compared to touring an aircraft carrier, that admission fee is extremely affordable: to board a Great Tang Empire aircraft carrier currently in service, the boarding standard is... a deposit of one billion dollars.
Yes, one billion dollars as a deposit, plus a purchase contract worth 900 million dollars as the remaining payment. Only after the money is paid in full does a country qualify to send its delegation to board and tour a Great Tang Empire aircraft carrier.
As long as a country has its own ports and coastlines, no one would want to miss such an opportunity. Many countries paid the fee and then quickly arranged for delegations to visit Linshui, where a Great Tang Empire aircraft carrier was docked for resupply.