I for one am happy to see the prices of gas fall lately. Even with that, there is a lot of variation in the prices. One gas station by my apartment has regular for $2.59 a gallon, while others I pass are as much as 40 cents lower per gallon! In other words, shopping around provides many advantages.
There is a web site that allows you to check gas prices in your area:
Select New Jersey, and you will be able to search by area for the highest and the lowest gas prices. How do they know? Well, people report them. There is a community of folks out there who take the time to contribute information to the site.
As of now, the lowest price in the state is $1.90 a gallon in Pleasantville (which is sadly an hour south of here), and the highest is $2.99 in Summit. That's a larger gap than I expected, really, but it does help my point. Great site to add to your bookmarks!