Not sure of your meaning here, but C1 is free to try for 30 days, then is paid software. Also unsure if you get a copy with a new Phase back, but the OP was talking about Leaf.
Capture One in DB mode is free and it works with all Phase One backs and with Leaf Aptus-II and AFi-II backs
For the Aptus and Aptus S one needs to purchase a Capture One PRO licence (PRO can be test-driven for 30 days free of charge for 1st time users)
Yair
PS the OP runs an older Mac/ OS setup which doesn't support Capture One, hence my recommendation to use Leaf Capture)