Credits are sold separately and are what you use to unlock songs. 1 song unlock costs 1 credit.

You can also get credits for referring your friends.

Songer Pro is a one-time purchase. Once you buy it, it’s yours forever. Pro gives you extra features like custom lyrics, high-quality downloads in multiple formats, faster processing, priority support, 10 free credits monthly, etc.

Pro doesn’t replace credits; it’s an add-on. If you buy Pro and also get, for example, 100 credits, you’ll have access to Pro features plus the ability to unlock 100 songs.