Google added support for regional availability and pricing to Google Merchant Center / Google Shopping feeds in the United States. Regional availability and pricing let you provide product availability and variable pricing based on your business presence and the location of your customer base.
Basically, you can now tell Google if your products are (a) available in a specific region within the United States and (b) if the price is the same in New York versus in California.
Google said you can "use regional inventory by specifying your business' regional pricing and availability to increase sales on products that may have previously been excluded from your reach. By using regional overrides to provide online product availability and variable pricing based on customer location, you can offer different prices for different regions or vary online availability based on regions that you define."
The example Google gave is that let's say "your business might only have a presence in certain parts of a country or specific states within a region. Or you might sell food products that vary in price depending on the region they are purchased in. Regional availability and pricing lets you directly address these situations."
Regional availability and pricing is available for free enhanced listings and Shopping ads on Google Search.
This help document will show you how to feed this data to Google.
Forum discussion at Twitter.
