I would first buy a domain name.
Then have that URL directed to your eBay listings UNTIL you can get your ecrater store(s) up and working.
Work on meta tags for your website that get you into the search engines AND pull members into your site to buy from you.
Always use a strong keyword base. Search out even avenue to find strong key words for your auctions, sales, meta tags and more.
If you have a store...read this link.
It is VERY important to diversify.
Find free sites, put up pages there leading back to your selling sites. Google search: Free website hosting
Join forums and in those forums have your links in your signature. Google and other search engines send out bots and will grab those.
The secret is getting yourself HIGH in the rankings as many have said.