-150 € and get your own Estonian ID instead of paying monthly fee to the registrar (and depending upon it's reliability). I don't know all the details of this process and whether it suits your need

Yes, I confirm, with e-Residency ID card it's very easy to buy an .ee domain.

Just make sure that you have a passport of the country from the right side of the world. Estonia doesn't accept certain passports at all (i.e. RU / BY) regardless of the residency of the owner.