It's easy. Find an old laptop with 512mb ram or more (you should be able to obtain one for free). Install a Linux OS (I like CentOS) Fire up apache/mysql or your server software of choice Point your domain name at your IP address.

I have a business internet connection at home. Even though it's mostly for personal use, it's a couple of extra dollars a month (not much) and I get 2 static IP addresses, and I'm explicitly allowed to run servers.

It's an excellent learning experience. But if it's for business, pay the money for a VPS!

Yeah, that's exactly what I'm thinking too. A coworker set up a home web server on an old C2D Dell machine, and when I ping it, it's responding quicker than the host I'm using.