According to Trulia,
"Average price per square foot for Graham NC was $87, an increase of 6.1% compared to the same period last year. The median sales price for homes in Graham NC for Feb 10 to Apr 10 was $135,000 based on 31 home sales. Compared to the same period one year ago, the median home sales price increased 14.4%, or $17,000, and the number of home sales decreased 27.9%.
There are currently 461 resale and new homes in Graham on Trulia, including 1 open house, as well as 54 homes in the pre-foreclosure, auction, or bank-owned stages of the foreclosure process. The average listing price for homes for sale in Graham NC was $178,736 for the week ending May 19, which represents a decrease of 2%, or $3,671, compared to the prior week. "
Concerning your storage building, I would be careful trying to give it value. Here is why. If you are selling your home, and you are selling it to someone that is getting an FHA loan (most likely), and the storage building is given value on the appraisal for the loan then the storage building MUST be at or better than FHA standards. In some cases, this means you may have to spend more money to bring the building up to FHA standards than the value that was placed on the storage building.
So unless the storage building is more along the lines of a finished shop, I would be very leery of trying to put a value on it. I would leverage the storage building more as a selling point to help sell the property quicker.