Truecar question

Hi all. I've been coaxed out of the lurking bushes to ask 2 questions.
I'm considering buying a Prius 2010 and want to ask those of you that have been around the block, and am particularly interested in hearing from the dealers. Has anyone utilized the website Truecar.com? If so, how valid would you say the information contained there is?
I've spoken to the internet salesperson at the local dealership in my area and indicated to him that I want to buy a 2010 utilizing the Sam's Club auto program. I asked him what the discount was and he indicated that he would sell me the vehicle at 3% over dealer invoice. Is this considered "a deal"?
Thanks in advance for any responses this may elicit.