Here is an older post of mine
zerothread/148207 that will give you some local San Jose Infiniti prices, and, yes, the Bay Area is among the highest in the country, so other parts of the country ought to be a bit less.
At Frontier Infiniti, the 30k mile service, with the "coupon" from their regular flyers, the price is $549 for an M45. Comparable to what the Nissan dealer quoted you ...
Keep in mind that Infiniti dealers are among the best for customer service, particularly with long-time customers who do use them for more than just warranty work. Of course, there are some rotten apples too, so exceptions do exist!
My experience with Frontier Infiniti in San Jose has been excellent. This is probably helped by the fact that I have bought three cars from them in the past seventeen years! But, I also have all the 7500 mile interval service done by them — only doing the 3750 mile interval oil changes elsewhere — and the warranty work.
Developing a good working arrangement with the Service Rep always helps. At Frontier, the original Service Rep I worked with back in 1991 is still there — now the Director of Parts — and the current Service Rep I work with (William Perry) has been helping me for over 10 years now, as I recall. He always makes sure that I am happy with their work and goes out of his way to get any issue taken care of by their best guys.
Z