i have made a website and hosted in my local computer using a static ip

where can i buy a domain name such as www.something.com such that it can redirect to my static ip

so that if i m using a page like a http://localhost/index.jsp it can be accessed by

http://www.something.com/index.jsp

does it matter if i run the server locally or i buy a managed web hosting server from a big company if the traffic is low on my site??

thanks