dar formato a dólares americanos

[andresdzphp]

Te dejo 2 servicios más y dan ambos el mismo resultado:

Webservicex

Código PHP:

function CurrencyConvertor($from, $to, $amount) {
    $url = "http://www.webservicex.net/CurrencyConvertor.asmx/ConversionRate?FromCurrency=$from&ToCurrency=$to";
    $sxe = new SimpleXMLElement($url, null, true);
    $rate = (float) $sxe * $amount;
    return number_format($rate, 2, '.', '');
}
 
echo CurrencyConvertor('PEN', 'USD', 8000); //2894.40
 

Yahoo

Código PHP:

function CurrencyConvertorYahoo($from, $to, $amount) {
    $url = "http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20csv%20where%20url%3D%22http%3A%2F%2Ffinance.yahoo.com%2Fd%2Fquotes.csv%3Fe%3D.csv%26f%3Dc4l1%26s%3D$from$to%3DX%22%3B&format=json";
    $data = file_get_contents($url);
    $json = json_decode($data);
    $rate = $json->query->results->row->col1;
    $result = $rate * $amount;
    return number_format($result, 2, '.', '');
}
 
echo CurrencyConvertorYahoo('PEN', 'USD', 8000); //2894.40