We're updating that. Right now it uses test ether so you don't pay anything, we want to get the cost down drastically before we start using real money. The cost is for something called gas which is a fee that pays ethereum miners to verify transactions onto the blockchain.

Here's a video to give you an overview of how to use it: https://www.youtube.com/watch?v=Ym8pVPJhlmw&t=233s