<?php

$users = array(10, 100, 1000, 10000, 100000);

$request_number = 24*60*60/5; // polling = 5s

foreach ($users as $user) {
    $requests = $request_number * $user;
    $computings = ($request_number * 2 * 256 / 1024) * $user;

    $request_cost = 0;
    $computing_cost = 0;
    if ($requests > 1000000) {
        $request_cost = ($requests - 1000000) * 0.2 / 1000000;
    }

    if ($computings > 400000) {
        $computing_cost = ($computings - 400000) * 0.00001667;
    }

    $total = $request_cost + $computing_cost;

    echo "Voi {$user} users sẽ mất: {$total}" . PHP_EOL;
}

// OUTPUT:
// Voi 10 users sẽ mất: 0
// Voi 100 users sẽ mất: 7.88048
// Voi 1000 users sẽ mất: 140.6168
// Voi 10000 users sẽ mất: 1467.98
// Voi 100000 users sẽ mất: 14741.612