Check tld-list.com and porkbun.com when looking for a domain to register, you'll often find cheaper than elsewhere

That said, I wouldn't use a registrar that didn't have good reviews, and I'd look at security policy, privacy policy, renew price, features list, and support options. Sometimes it's worth paying more.

After you have the domain, if it's important to you, try to get support to change it for you or recover your account without a valid email address. You'd be amazed how easy it is to compromise many registrars through support.

And set up auto renew... Once it's gone, you'll regret it.