Hi,
The major advantage of having your own domain is branding and control. With your own domain you can create brand awareness for your visitors. With a sub domain hosting senario your may be able to get a dedicated URL (and even email - you@yourdomain.com) but you will always have to rely of the providor, and this takes the control of the domain, content (to a degree) and your email systems out of your control.
Domain hosting does not have to be expensive. I know of various hosting providors that can offer decent packages from ?5 per month.
Please feel free to from me a line on kmcdonnell@mppmanagement.com if you would like a list of suitable vendors.
Frontpage is one of the easist authoring packages to use as it is very similar to using Word. This might be perhaps the best application to start with until you get to grips with the behind the scenes stuff.