Bit like how long is a piece of string
, can only answer in short queries, basically for a website you need
Domain Name, i.e.
www.yoursite.com (small expense)
Hosting -Space on the internet to host the files, Various options available basically for a retail site you will need a hosting account to support databases and either PHP/ASP depending on what language you site will be written in.
Web Site - You will need to code a website or use a free site package or hire some one to do it.
On a personal note i gave provide a service/guidance for all the above.
In terms of advertising and google probaly best posting in the seo and google section. SEO bit of a black art in my eyes. But to place adverts in is fairly easy and whether u use a code or a package as above this will be included to an extent.
So to be so short in the explantion just could write a book on bits of it
.
If i find any good tutorails i will post them, in the middle of writing one or two myself, also may want to try mkpitstop.co.uk homepage MK has some tutorials on their on seo and stuff