I agree with all of these answers but I must also mention altho it is true the sellers agent is obligated to get them the most money, that agent is also obligated to give them the facts pertaining to thier property such as market value for that area for homes that compare to the sellers. A good sellers agent has done the comps and will price the house accordingly. The agent needs to know your reasons for selling also, this can make a difference in the listing price. Take a look at the expireds, solds, and actives that are comparable. How long have they been or were they on the market? Did they have offers on them? Were these homes listed with different agencys previously? How much and how often have they lowered the price? A good listing agent will take all of these things into account when helping someone set the listing price. A good buyers agent will get all of these facts and do their own comps and advise the buyer on what he or she beleives would be a good offer to purchase. It will also depend on the buyers reason for buying, this house, this area, is there an urgency? some of the same things you would need to know from a seller. What is the motivation?
The taxable value and the listing price are apples and oranges.

Hi Mary,
Tax appraisals rarely represent true market value - they can be low, or they can be high. Tax appraisers don't even go into the propertites when they do their appraisals!
The best way to make sure you are not overpaying for a property is to work with a good buyer's agent who will do a market analysis and determine the value of the property in today's market. I even tell my buyers to ignore the listing price, and to look at what the market analysis says to determine what you should offer for the house. Listing agents are legally obligated to get the most money possible for a house because they represent the seller's interests. Buyer's agents are looking out for the buyer's best interests. If you use a good buyer's agent, they will make sure you know the true value of the property you are considering.

Mary,
David is right. Property tax appraisal is from the court house, it is strictly for tax purpose. The way they estimate the house is not the same at all. The accurate appraisal is the actual one done by the appraiser.

Property tax values are not the same as market values, you need to get an appraisal, or to start a cma from your Realtor.