Hi Chris,
Apologies for not getting back to you quicker.
I believe that Daniel was correct. There are only so many slots available on one page. Even if you search for Grand Theft Auto, there are only roughly 20 positions for a consumer to choose. Then they are listed by price, as most consumers want to see them by price.
You can really shine in the shopping section like this by getting a large number of reviewers to review your product. I don't know of many people who use the Google Shopping area without the reviews section. so Even if you were selling something for .99, if you had zero reviews you were probably more likely to not get the click.
These ads have always been the cheapest I've ever run. I would definitely recommend playing with your bid and monitoring the impressions, click through rate, and conversion totals. Every business has its own difference when working with the Shopping campaigns so I would highly recommend spending some time to really isolate your top performing products from your feed and bid on them individually. The more specific you make your bids the less you will likely end up paying.