There are a couple of things related to the value of domain, for instance, the uniqueness in the name, length of the domain name, keywords usage, and also extension used. Different domain extensions have different prices. For example, ".io" might cost around $35, ".online" might be about $32, but you can get a ".com" domain for as little as $8.You need to remember, the extension does not help in ranking, your domain name does. In other words, Top Level Domain does not help in ranking, Second Level Domain does.