I have an S4 mini that is unlocked. Can I just buy a sim card thru Republic and use it this way?
I’m afraid the direct answer is no. Details follow:
You may bring any of the qualified phones as indicated by Republic here: Bring Your Own Phone FAQs. You’ll want to be certain that the phone you wish to bring is an exact model number (and in some cases build number match) for those listed.
Everything else one might want to know about Republic 3.0 is here: Republic Wireless 3.0 FAQs.