The MTS Advanced Invoice add-on helps you craft professional invoices, automatically generate new invoices and recurring invoices, and send payment reminders.
gave this add-on stars.
This module added a crucial feature to our SuiteCRM installation, as we were missing out on a lot of subcription billing due to our manual processes. This is one of several add-ons we purchased from this developer--he is very responsive and quick to support any issues or requests. Highly recommended.