You tested it. 1.0 is half price.
Your beta key covers the 0.x betas it was issued for. 1.0 is where the paid licence starts, so once you update, installing needs a licence. Because you ran the betas, that licence is $7.49 for you rather than $14.99. Same one as everyone else: 3 Macs, paid once, every 1.x update included. Scanning stays free either way.
Paste your beta key. Floodtide shows it under Settings, then License.
One upgrade per beta key. You will get a new key by email after paying; that is the one to use from 1.0 onwards.
Questions people actually ask
Does my beta key stop working? It keeps licensing the 0.x betas it was issued for. It does not license 1.0, so the moment you update, installing asks for a licence and Floodtide puts this offer on screen to explain why. Scanning keeps working either way, as it does for anyone whose trial has ended. Updating Floodtide itself keeps working too, so you are never stuck.
I lost the key. If you are still running Floodtide, it is in Settings under License, behind the Reveal button. If the Mac is gone, email raf@bhopstudio.com.
I already bought a licence. Then 1.0 is free for you and there is nothing to do here. Every 1.x update is included in what you paid. Find my license if you have mislaid the key.