Google has implemented complete pricing and a “free shipping” filter that instantly makes shipping a critical data point in your Google feed. It appears that both shipping and tax information must be configured either in the Google Base interface or in the feed for this to work correctly.
It’s pretty clear that many merchants do not currently have these data points set up. I searched on iPod and saw the first result had 52 sellers. When I clicked the free shipping filter, that number dropped to one. A quick glance at the product page indicates that though there were a few merchants with tax and non-free shipping configured, most of the merchants just have blanks in those areas. So if they are offering free shipping but don’t have it or the tax configured correctly, they are probably going to lose a lot of traffic this weekend.
If you offer free shipping, you should jump on this. If not, it may not be too critical because the presence of this data does not appear to have much weight in the display algorithm that dictates how offers are ranked. Since Google remains (for the time being anyway) free, getting clicks from users searching for shipping and tax information isn’t necessarily bad. It may make your conversion rate appear lower, but free traffic is free traffic and there will likely be some retention.