First one - seems a great idea . Websites are cheap and pretty hassle free.
Hosting can be pretty cheap and some provide free software which can be useful. I did all mine before I found this out .
I use 1&1 who seem pretty helpful
Re the design
People like pics and as few clicks as possible (but Im sure you already know that) so I would have the first page split into the 4or6 pictures of the most popular catorgaries of items so you just click on the pic.
Also I assume that you would have full contact details on the front home page and that they are missing cos it's an early draft.
Finally , and again you've probably thought of this as well, speak to waynne as he knows much more than I do.
And finally Go for it