Hello,
Regarding your description, you do have several "free subscriptions" and I don't have the feeling that users can change between them.
So it looks like you would need a custom plugin to perform the creation of the free subscription depending a custom field that you would add into the registration process.
Thus, the plugin will create the subscription (for one of the bronze plan) and could also do the free renewal.
Thanks to that, customers would be able to do an upgrade using the classical system and pay for the upgrade and then renewals.
Because the free subscription is for the moment too specific, it's not something we can add into HikaSubscription because it won't fee to every user needs.
But we will think about it and see if we can find another solution, flexible enough, which will be useful for every HikaSubscription users.
Regards,