<?php
 
error_reporting(-1);
 
function calculateCredit($percent, $monthlyFee, $onceFee, $creditSum, $payout) {
	$sum = $creditSum + $onceFee;
	$totalSum = 0;
	for ($i=0; $i < 369; $i++) { 
		$sum = $sum * $percent + $monthlyFee;
		if ($sum >= $payout) {
			$sum -= $payout;
			$totalSum += $payout;
		} else {
			$totalSum += $sum;
			break;
		}
	}
	return $totalSum;
}
 
$creditSum = 39999;
$payout = 5000;
$homoCreditTotal = calculateCredit(1.04, 500, 0, $creditSum, $payout);
$softbankTotal = calculateCredit(1.03, 1000, 0, $creditSum, $payout);
$strawberryBankTotal = calculateCredit(1.02, 0, 7777, $creditSum, $payout);
 
echo "homoCredit: {$homoCreditTotal} руб. \n";
echo "softbank: {$softbankTotal} руб. \n";
echo "strawberryBank: {$strawberryBankTotal} руб. \n";