If you register with Consumer Reports on line (it's like less than 5bux a month) You can find the dealer invoice price (what the dealer paid) for any car. They also have tons of buying advice. When you negatiate, start from the invoice price and move up. Don't go by the sticker, it means nothing.
As for pricing the one with 7,000 miles, check
www.autos.msn.com
Not sure if the 2003 is old enough to bring up used car prices, but if it is you can find it here. Just go to find a car on the left. Also try
www.kellybluebook.com to price the used one. This site also has lots of info for new car buying.
Good luck!
Peace

Chris