During the beta
Everything is free, with no key: download DropWave and install the plugins from DropWave Manager.
From release day
DropWave, DropWave Editor and DropWave Tune each need a licence. Buy the ones you use, and you get a key by email. Enter it once per computer in DropWave Manager (Settings → Manager in DropWave): one key works on up to 3 of your computers, and you can move it by deactivating one.
Until a key is entered, DropWave won't open and the plugins pass audio through unchanged, so nothing in your projects breaks.
The release date and prices are announced in the app, here and in the Discord before the beta ends.
Questions
Write to hello@getdropwave.com.