Starting a domain registrar costs anywhere from $10,000 to $100,000, depending on ICANN accreditation and infrastructure. Ongoing fees and technical setup add to the investment.
If domainers were smart, we could already be the governors of #1 registrar in the world, even Godaddy would be a beggar compared to us!
P.s. I have read that you need more than 500K when I looked.
It's a LOT cheaper to buy a current registrar than to set up a brand new registrar. Lots of red tape to go through, and it can take a long time to try to set up a new registrar from scratch.
Last I checked the application alone was around USD $3-5k. You also have to show USD $75k+ in the companies bank or LoC from what I recall to prove you have money for operations (they do make some exceptions if you can prove low overhead, sustainability and profit/revenue). Haven't checked since 2020 so numbers may have changed.
I would honestly test the water first by just making a white label registrar leveraging other registrars API's like dynadot, namecheap, enom, etc. Once you are established and are doing well, then apply for ICAAN acredation and migrate the domains to your own accredited registrar once it comes time for users to renew their names.
edit: Or as some other users mentioned, you can skip the red tape and buy an existing accredited registrar.
Note: that profit margins on domain names are razor thin for registrars - you would have to consider offering other services such as hosting or try and compete with drop catching/auctions to make some profit
It's expensive to open a new one. Just buy it cheap from bad current registrar and close it down.
It's cheaper to close than to open.
Btw, you are not serious so why you asked?