Soundiiz's paid offers are based on a subscription system (except the "one-time" offer, which could be better suited to your needs if you only want to use the Soundiiz transfer feature without commitment).
That means you can subscribe to monthly billing (you will pay per month) or yearly billing (you will pay once per year for the whole year) and then cancel your subscription at any time in your user settings.
However, if you only need Soundiiz to do a one-time transfer to a music service, you can take the monthly billing and do the transfer process. Once you have checked all your data in the destination service, cancel your subscription.
You can get more information about the price on our Pricing page & offers.