Each time your subscription renews, you will get the crowns for each month's worth.
You should have gotten a pile of crowns when B2P went into effect; these crowns included all the upcoming months you still had left on your already paid for subscription.
I won't see new crowns one of my accounts until August, and another in about two weeks or so.
Hope this helps,
Ravalox Darkshire Developer of Wykkyd ESO AddOnsandRavalox' AddOns Co-Founder Brotherhood of Redemption ESO Branch Brotherhood of Redemption (A DC faction guild) http://eso.borguild.com *Always accepting worldwide applications for the PC NA server*
You get all the crowns for the period you have subscribed for at the time of payment, so if you took say a 6 months subscription you'd get them at the time of payment and wouldn't get any more over the 6 months until the next renewal. That's as I understand it, anyway.