<?php

function bestBankCalculator($percent, $commission, $years, $creditSum, $payout, $downPayment){
	$creditSum += $downPayment;
	for($i=0; $i<$years; $i++){
		$creditSum = ($creditSum * $percent + $commission) - $payout;
	}
	return $creditSum;
}

$homoCreditTotal = bestBankCalculator(1.04, 500, 12, 39999, 5000, 0);
$softbankTotal = bestBankCalculator(1.03, 1000, 12, 39999, 5000, 0);
$strawberryBankTotal = bestBankCalculator(1.02, 0, 12, 39999, 5000, 7777);

echo "homoCredit: {$homoCreditTotal} руб.\n";
echo "softbank: {$softbankTotal} руб. \n";
echo "strawberryBank: {$strawberryBankTotal} руб. \n";