Comodo signing services pricing varies by type and duration.
(All prices are subject to change.) The legacy certificates are
signed with an older root and are normally not needed unless older
mobile devices (e.g. Windows Mobile 5) are clients and those
clients are unable to install the current Comodo root.
Comodo also signs test certificates that are good for 30 days and are renewable. They do not sign test certificates with the legacy root.