If you're going to go with a VPS and have it unmanaged, you need to understand that x10 is only responsible for keeping it connected to the internet and physically running. This doesn't include installing operating systems, editing settings, and helping with web servers and other random tasks involved with running a VPS.
The managed VPS is a little bit easier to administrate since x10 staff will help install your cPanel and setup nameservers for you, but if you were going to go with a VPS you should think about getting WHM/cPanel. Web Host Manager (WHM) is the actual program BEHIND cPanel that controls all the hosting accounts. When you get a WHM/cPanel license you get both products... WHM is what you see when you manage your server, cPanel is what you see when you manage one of the hosting accounts on your server. You would be able to, directly from WHM, install and update certain perl modules, update mysql, recompile apache and php with EasyApache and it makes running your own server much much simpler. If you're not an advanced user and a linux nerd you might have trouble with doing all command-line server configuration.
The free panels that most people are talking about WORK but again, they normally require a bit more expertise since they are free and don't have the support and popularity that WHM/cPanel has.
Payments are done either through PayPal or processed by credit card through a payment gateway. If you're unsure then just use PayPal. If you use PayPal to pay for your VPS account you will not be charged anything but the price of the panel, the PayPal fees are paid by the seller not the buyer just like credit cards work.
The cheapest unmanaged VPS is 8.95/mo with WHM/cPanel it becomes somewhere around 18.90/mo so it's almost a better deal to buy the managed version which is 28.95/mo and includes simple management of the important necessities like your WHM/cPanel install and a compile of PHP/Apache for you.
Oh and if you don't know why cPanel is free on the free hosting it's because WHM is what costs money, cPanel just comes along with it for people who have an account on your server and in WHM. So since the free servers each have a WHM licesnse they have cPanel, thus people calling it "WHM/cPanel" hope that explains it.