Domain Business
Have you ever thought of what google.com, yahoo.com, actually are ? Technically speaking they are IP internet protocol addresses in real that are made in such a way that will lead to the webpage of the domain owner.

Some people do it as a business in a way that they will register the domain names and sell to the customers if needed. These domains are parked at PPC company.
Once domain is registered the value of the domain increases as the popularity of the domain increases which in turn increases throught the traffic it drives.
Domain Registration
Lot of things to be followed and taken care while and after registering a domain. Before registering a domain name one has to check the availability of the domain names. This can be done at the domain registering or web hosting sites like godaddy.com, 123-reg.co.uk, business.BT.com/domains, Daily.co.uk, 1and1.co.uk, Names.co.uk, One.com/Domain, NetworkSolutions.com, MadDogDomains.com, CheapDomains.com.au, webcity.com.au, CrazyDomains.com.au, Unlimited-Space.com.au and so on.
In the above mentioned sites one can check the availability of the chosen domain names and register at the said cost. Usually the duration of the ownership is 1 year. But somepopular sites do for 5-10 years as well.
TLD
TLD stands for Top Level Domain. This refers to the suffix attached to the domain names. These TLDs are predefined and sorted and chosen based on the application. For example .edu is taken by education institutions, .com is taken by commercial entities, .biz is taken by business organizations and so on.

If mistakes are done in registering a wrong name then the amount paid will not be refunded. Most of the domain registering companies operates on the non-refund policy. These registered domains will become active enough to be accessed by the internet users worlwide within 48-72 hours.
When the ownership period is over or yet to over, the owner of the domain has to renew the ownership period if he wants that domain name belong to him. Else if the period is expired, anyone can take ownership of that particular domain by buying that.
Offers
Some offers are being delivered by the web hosting companies to the customers like 1 year free domain name, Domain names are low cost, Domain names starting at Re 1, Domain names starting at $1. One should go for the reputed and well known web hosting companies to get the 24x7 technical supports.