[420365247]

Often, I am willing to pay a few bucks more to purchase from a retailer I like...or who I am comfortable doing business with.

I think you may be assuming that people only check one place for a price...consumers tend to look at a few merchants. They compare the price of the product and the shipping cost from the merchants. Another item to consider, is that many shoppers also look for free coupon codes to get free shipping or 10$ off from a merchant.

What I do like about your idea is that the prices are checked via crowdsourcing.

I think your site UI could be a little fresher.