Rather than reply to your PM, I'll do it here for the benefit of others in the future.
This forum has a search facility, you will find many of your answers here almost instantly rather than waiting for me to visit the forum again and answer you. When you cant find the answer, then look for other similiar forums or try a major search engine like google (
www.google.com).
A standard domestic PC may run 24*7 OK, however they are generally not designed as server class machines, so don't expect reliability, it may work well, it may not.
If you want a cPanel license, then an external license will cost you around $50/month, this will need a static IP for the registration of the license.
A domestic broadband connection is optimised for download, to run a server you need high upload speed (or very low numbers of visitors), some ISP's prevent you from running a server on your connection, others prevent you from running a business over a home service, read your T&C's and ask the question of your ISP.
Other issues, your house insurance may prevent you from running a business from your house if it doesn't class your property as a business property. If you're still living in your family home, ask your parents permission before starting a business.
A datacenter will generally have redundant Internet connections, redundant power feeds, most probably also a backup generator, it will have air conditioning to keep the servers operating efficiently, high security, staff on call 24*7 to fix issues, SLA's with power and network companies to ensure the light's stay on.
Your best bet is to get a reseller account (we do them cheap
) or rent a small server or VPS, you'll get better connectivity, cheaper cPanel license and customers email won't get filtered by AOL and many other ISP's SPAM filters due to originating from a residential IP.
You may also want to research the terms "kiddie host" or "bedroom host" as this is how you will appear to others, however genuine you may be in becoming a host provider.