You rent things like domain names and hosting. You can even buy the rights to the code used to make a website. You can even buy control of a website and a domain but you are still going to have to pay for hosting and renewal of the domain name. However you really can't buy a website, not in the way most people think of buying. Just to clarify what exactly are you talking about buying/renting? Is it the domain name, the code, or rights to the host and domain name until it needs to be renewed?
I'm inclined to think this is a scam of some kind. If the site were profitable why wouldn't they just hire people on to run it and then just pocket some of the income? As has been mentioned they could be using various tricks to drive traffic to the domain. They could be working with the hosting company and plan to charge exorbitant amounts when you have to renew your agreement with them. The host could be malicious and harvest user information.
If you want to get into the website business you want to learn how to install/run a lamp server and write html/css/php/perl/mysql. Others might disagree on what OS, scripting languages, and/or database to use, this is just my preference. Don't forget to capture your traffic (you'll learn more) and you should also try to figure out a few of the helpful blackhat tricks for boosting web traffic and ad revenues. SEO (blackhat or otherwise) is a skill set all it's own. Try to learn it but don't be ashamed if you have to hire someone to put the finishing touches on (same goes for hosting or coding). If they are good it's worth it.
With virtual box you can give turnkey LAMP a spin if you just want to jump in head first. Don't use it in a live environment however, I don't trust it to be secure. Limit networking to either the host machine or other VMs. Limiting it to other VMs is very secure but a bit of a pain if you don't have a lot of RAM and at least two processors.
http://www.turnkeylinux.org/lampstack
Even if you don't come up with a profitable website you walk away with marketable skills. Jumping into website hosting and design by buying a supposedly profitable website is doomed to fail and cost you a good bit of money. Better to learn with a little host you setup on a local VM and maybe get some certs if you want to look for employment based on your hosting skills.
