Please read my colleagues' replies ... they're packed with very useful information. All that aside, however, if your objective is to purchase the home for the assessed tax value, it's just not going to happen. Once you have the "comps" in your hand, you can pretty accurately determine its market value ... and if the price is totally out of the ballpark, it's best to move on.
Of course, this doesn't mean that a cash buyer won't pay whatever the seller is asking. Be it a house, car, or anything else, something is worth what someone is willing to pay.
You need a Realtor to provide the information, since home sale prices are not public record in Texas ... and given that there is no cost to you as a buyer, why wouldn't you work with one of us?
If I may be of further service, please feel free to contact me.
Trend Setter Realty