It's important to understand that only a licensed appraiser can tell anyone the "true market value" of a home. Real Estate brokers like myself can do a comparative market evaluation and will come close but we are not licensed to give "true market value". If you are currently looking to purchase a home in that area the best thing to do is hire a buyers agent who would be able to give you the best and most accurate data as well as help you analyse the data. Unless an agent has been hired by you to represent you they by default work for the seller and can supply you with comparable sales but are not able to evaluate this data for you or advise you about offering prices.
If you are currently looking to buy in the Garner area feel free to contact our office through the link here in Trulia. I own the Real Living office on Vandora Springs in the Forest Hills shopping center and we represent many buyers and sellers in the area. I have sold over 1500 homes in the Triangle and would be happy to help.