I take back part of what I said.
When I was there all the stations routinely sold for the same price. I just checked gas prices, and they do vary a bit now. Apparently it was because of this state law:
http://www.heraldextra.com/news/opinion/surprise-price-controls-in-utah/article_3d2a6b9f-5af1-5911-9d20-742c219e6dbb.html
