Bruce, It all depends on how much time you want to dedicate to the search. You can definitely do it yourself, it may take a bit longer. To get a true accurate trend, you would need to see what has closed within the last few months, compare and make appropriate adjustments. If you are inquiring this info to possibly put your house on the market, I would recommend speaking with an RE agent. They can answer all your questions and provide you with detailed info.
If you're looking for a local agent in the Mabank, Tx area, I can help you. Feel free to contact me if I can be of assistance. You can reach me @ email@example.com