Here is how I would personally get a reasonable price for a car I would like to buy or to sell:

If you are buying goto Carfax and make sure car checks out. If you are serious about buying. Its worth the $25.00 or so.

Selling and buying:

Goto Autotrader and get price (I will call it X). Use your zip code and go a distance of about 200 miles.

Goto Kelly Blue Book and get price (I will call it Y).

Goto NADA and get price (I will call it Z).

Average Price = (X + Y + Z)/3

If you are buying or selling remember that:

Upgrades do not bring that much money, so don't be fooled by all that extra stuff the previous owners installed. These items are very negotiable.

If you are buying:

Take it to a competent shop and have it appraised/evaluated before buying.

Buying and selling:

Things to ask. Ask for or provide documentation for:

1.-Does the timing belt need to be replaced? When was the last time it was replaced?

2.-When were all the other belts replaced?

3.-When was the clutch replaced? If the car is manual.

4.-When was the thermostat replaced?

5.-When were the Positive Crankcase Ventilation (PCV's) valves replaced?

6.-When were the transmission and differential fluids replaced?

7.-When was the engine coolant replaced?

8-When were the upper and lower radiator hoses replaced?

9.-When were the heater hoses replaced?

10.-Do the valves need to be adjusted every so often? When was the last adjustment?

11.-When were the spark plugs and air filter replaced?

12.-Have the suspension components been replaced? Struts? Springs?

13.-Are there any leaks, coolant, brake fluid, power steering?

14.-Has the heater core ever been replaced?

Items to check for:
new belts
new timing belt
new water pump
new water hoses & new antifreeze
new tires
new oil
new tranny/diff fluids
new pcvs
new spark plugs
new batt
new fuel filter
radiator
universal joint
drive shaft