A seller's advertised or list price should be treated as only a rough estimate of what he or she would like to receive. Some deliberately overprice, while others ask for close to what they hope to get and a few actually underprice their houses with hopes that potential buyers will compete and overbid.
The appraisal price is another estimate of value. The appraised price is how much money a professional appraiser estimates the home to be worth and usually is based on sales of comparable homes in the same area.
Purchase price and sales price are the same thing. Both terms mean the amount of money the successful buyer actually pays out to purchase the home.