Are Cronjobs free services or do they require payment?

Cronjobs are not free services and often require payment to use. However, there are some free options available, such as using a web hosting service that includes cronjob functionality in their plans. Alternatively, you can set up a cronjob on your own server if you have the technical knowledge to do so.

// Example of setting up a cronjob in PHP
// This code snippet will run a script named 'my_script.php' every day at 3 AM

$cronjob_time = "0 3 * * *";
$cronjob_command = "php /path/to/my_script.php";

exec('echo -e "`crontab -l`\n'.$cronjob_time.' '.$cronjob_command.'" | crontab -');