AAA Discount: I just saw on their site that the AAA discount is 10%. All I know is that at checkout, they said I saved just over $3 from an original price of some $13.80, which I assumed was my AAA discount. Evidently it was more than that. YMMV.
Its nice here when there isn't a consensus, so you can do what you want and nobody gets mad at you and says you aren't following the advice when you start a thread.
NAPA had all three bulbs for $10, which was too much of a discount compared to one for $26 at my local toyota dealer, so I went with them. I was surprised at my AAA discount, which was something around 25%. If you do buy from NAPA and are a member, go ahead and give them your number at checkout.