Building a website.

I am building the website www.monstarauction.com. A brand new online auction that allows sellers to earn more money selling online with the lowest posting and final cost in town. Offer their buyers crazy deals and still pocket profit. Enough about that. My thing now is how do I earn the trust of the seller to want to use my service as the next step in doing business online? I have plenty of ideas running through my mind and the website continues to grow, but I'm still looking for that edge. Check the site and tell me what you think.