Actually the original idea was to allow each gas station operator to determine their own prices every week (as long as it is lower than a government-set ceiling price).
Then when the day came to implement the weekly price updates, the plan quietly got swept under and we are back to prices that are uniform across all operators.
do gas prices in the states fluctuate alot every day? What factors affect the prices of individual stations? location? number of pumps? Are some brands generally cheaper than others?
Prices do not usually change a lot during the day but may change from day-to-day. A few days ago the price jumped 5 cents per gallon (3.8 liters). I am guessing that location has a lot to do with price. If the location is bad, you need a good price to attract new customers.
Sometimes a gas station lowers prices to attract new customers, and once those customers start to like that particular gas station then they can raise compared to other stations and people do not care much anymore.
You had some great questions. Sorry that I do not know better answers.
No worries, your answers are very helpful. Thanks!