Creating a WordPress Website using nicepage

Is WordPress Free to use or do I need to pay to use the Dashboard for my nicepage plugin after uploading it?

Also, nicepage is my host and Theme builder. I’m using WordPress for the PHP plugin Chat Box by 3CX…the Chat box only works in WordPress. So I’d like to upload the nicepage theme builder, add the PHP Chat Box code to nicepage and continue to host with nicepage. Is that possible to use the Dashboard for free or do I need to pay for it?

The page I need help with: [log in to see the link]