<?php
    function getPayment($percent, $comission, $basicPayout, $credit, $payout) {
        $payment = $basicPayout;

        while ($credit > 0) {
            $credit = $credit * (1 + $percent) + $comission - $payout;

            if ($credit <= $payout) {
                $payment += $credit;

                return round($payment, 2);
            } else {
                $payment += $payout;
            }
        }
    }


    $credit = 39999;
    $payout = 5000;
    $banks = array('HomoCredit' => getPayment(0.04, 500, 0, $credit, $payout),
                   'SoftBank' => getPayment(0.03, 1000, 0, $credit, $payout),
                   'StrawBerry' => getPayment(0.02, 0, 7777, $credit, $payout));


    foreach($banks as $bankName => $payment) {
        echo "Плата у $bankName: $payment руб.\n";
    }

    $cheapestPayment = min(array_values($banks));
    echo "\nНаиболее дешёвая цена ".$cheapestPayment.' руб. в банке '.array_search($cheapestPayment, $banks).'!';
?>