
Most new blogger/wordpress users start with a free subdomain such as subdomain.blogspot.com or subdomain.wordpress.com and if some one wants his blog to be ranked high on google search he should buy domain that ends with extension like .com, .org, .net or .info which are the most preferred but the best of them all is .com domain, also it's preferred for google search (everybody use google for searching things ).
where You can get your new Domain Name
There are a lot of companies around there on internet that provide Domain names.
GoDaddy:
GoDaddy registerar company has been around for a long time and almost millions websites get their domain names from them.
HostGator:
HostGator is another large company that provide hosting serviceand also domain registration but they are tricking users with low initial prices and then gradually rise high the renewal fees.
NameCheap:
Namecheap, this one well known for their prices (0.88$ but not for TLD domains .com, .net. org etc).. Their service is simple and straightforward so you can register your blog's domain there and they 24H support and they don't annoy users with email ads. Also you can find a lot of domain name registerars on internet if typed on google search for a domain registerars.
How to Get Top level domain (.com ) with less than a Dollar

All domain name registrars provide top level domain names with different prices but not with one dollar unless you want other domain such as .club, .space, .store and so on. Here with this simple method you can get a top level domain name with less than on Dollar.
All you need is just a vpn with us server, and if you are familiar with kpn tunnel or http injector ssh proxy vpn create ssh server account on fullssh.com which provides various servers with usa IPs or you can create ssh account on speedssh.com with the same services and on your application, I mean http injector edit DNS to Opendns which is 208.67.222.222 for the first and for the second type 208.67.220.220.
Remember not to use default DNS which is your ISP.
On your browser you need to clear cache and then go ahead to GoDaddy on United States Site us.Godaddy.com and Choose Your Domain as .COM you will pay less than one Dollar for your .com domain name.