Web3Domain.org came up with , let’s earn together option.
As like other domain sellers, you can be the owner of your own domain.
Register primary domain (Eg. “ABC”).

Now anyone register & mint “someone.ABC”, the 50% share will be given to the owner of ABC domain.
The earning is done only once during the time of minting.

You can set your own price in $MATIC. It can be less then 1 cent.
You can increase/decrease the price anytime you wanted.

You can sell this domain at web3domain.org or you can create your own website and let users to mint on your site. It is same in both the cases. 

This way, we can earn together in decentralized partnership. As this 50% ratio is mentioned in smart contract which will remain forever.

There is also the option that, you can restrict anyone to register your subdomain.
In this case, only the owner of domain can mint the subdomain.
At this time the minting cost will be ZERO.