Datum manages to give us, the producers of this data, a part of the money share.
That sounds great

is there any cost per month subscription per user? is thee any cost information somewhere?
It would be pointless. They can't charge you to give them your data.
What kind of a fee are you talking about? They will buy from us, we will not buy from them

It's too early to discuss monetary payments for your data. It's important to understand that you're just one user so the money you can make will accrue in time not right away.
Although still early to discuss about it, but honestly, do you really want to sell your information to make money? I do not think this is a good idea, there are a lot of people want to keep their information, even they are only person normal and is not famous person, but they still want to keep safe their life instead of use it to convert to money.