This is the 10605th most frequent Swedish word.
kostnadsfritt
Free of charge.
Here, 'kostnadsfri' is used as an adjective describing the service, indicating that it does not cost any money.
Denna tjänst är helt kostnadsfri.
This service is completely free of charge.
In this sentence, 'kostnadsfritt' is used adverbially to describe the manner of registering, emphasizing that the action requires no payment.
Du kan registrera dig kostnadsfritt på webbplatsen.
You can register for free on the website.
Here, 'kostnadsfria' is an adjective in plural form referring to solutions, indicating that they do not involve any cost.