VPN services are not philanthropic companies created for the public good. They, like other organizations, have their own expenses and invoices issued by contractors to pay for services provided, such as electricity, or rent space. Also, the VPN service must contain a staff of employees, and therefore pay wages or equipment that has a payback period. Now scale all these costs to the numerous countries where the service equipment is located.
Also, the VPN service must comply with the laws of the country where it is located and officially registered.