Domain names are your Internet Property and can get very valuable depending on traffic / people visiting!
domains cost from £3.75 per year and you will definately need one!
Once you have a domain you will need hosting, this can be from free upto a few hundred per month.
I would normally pay for a small site about £30 per month!
Pm offers domain names and hosting for it's customers only!
when choosing a domain you need to bare in mind a few things, I normally buy a short one to
market direct to people and a long one to gain an advantage in search engine domination!