You’re a good dad. Not just because you helped your son, but even more so because he already had the confidence of knowing he can ask you a question like that.

Keep on doing what you’re doing. You’re a good dad.

Looks like nobody pointed out the obvious here:

Domains cost around 10-20$€£ per year. That amount is rent, paid to the registrar.

If you find a domain that costs more than that, then you are not dealing with a registrar. You are dealing with a domain squatter that owns the usage rights to that domain name, and the price is what they demand to transfer that right to you.

If you’re stupid enough to pay that, you’ll still need to pay the actual fee to the registrar when the next billing period starts.