I don't know what exactly you are doing but it seems like you don't understand what pricenomics are doing. They tell you how much your stuff is worth if you are trying to sell it. It is not a social shopping site.
On your site, the main call to action is to post something I've bought. Why would I want to do that? I also couldn't actually figure out how to search for an item (I entered "Macbook Pro" into the filter but didn't find what I was looking for.)