Where's the cheapest place to buy a domain?
Domain registration prices are very similar regardless where you go (a dollar more or a dollar less.)
I find Google Domains to be the best option in general. They're certainly more trustworthy (both on your account security, and issues with their system) as any small company can be. And they also have good free email forwarding (so no need for an email provider and setup if you don't need a separate login and inbox), and they also come with free private registration (which you need if you don't want your name public for all spam calls to start coming to you, the aforementioned gkg charges an extra $2.85 for it.)