An example based on ipdata.co, which gives you the currency symbol and code directly from an IP address.
This answer uses a 'test' API Key that is very limited and only meant for testing a few calls. Signup for your own Free API Key and get up to 1500 requests daily for development.
The API also has 10 global endpoints each able to handle >10,000 calls per second!
$ip = '78.8.53.5';
$details = json_decode(file_get_contents("https://api.ipdata.co/{$ip}?api-key=test"));
echo $details->country_name;
//Poland
echo $details->city;
//Głogów
echo $details->currency;
// PLN
echo $details->currency_symbol;
// zł
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I created this service.