As to our use of Gasbuddy... I'm not talking about searching after the fact and driving back 10 miles, or to drive miles out of the way to some tiny gas bar in the middle of a town to save a few pennies.
But it sure has been nice to know well ahead of time that the truck stop on the far end of town is 40+ cents cheaper than the ones on the near side.... or that the one on this side of town is the place to stop. That has happened regularly... once I calculated we saved over $100 in a single week of travel; I figure GasBuddy has saved me $500+ since I started using it (I don't manually track how much I saved on each fill-up from highest price... that would be way too much work! But I've traveled 30,000+ miles in 3 years so it adds up...)
So we're not talking pennies here; you can buy some tools with that right there
... and I didn't do anything other than pick which truck stop to use when I needed one...
Like you, we start looking for fuel about 100 miles out. Gasbuddy makes that so easy - I tell my wife I need fuel in xx miles and my wife starts searching on the app. Often she will skip the town ahead because she knows we can get to the next one where it's cheaper. Once she finds the ideal stop, she tells me well ahead of time how many miles ahead, which exit to look for, what station it is, and whether to turn left or right at the bottom of the off ramp.
I also like how easy it is to use when fueling up: enter just 2 things - your odometer and the dollar amount. From the built in GPS it already knows which station you are at, what the fuel price is, then calculates how many gallons you filled. If the fuel price is off, you adjust it and it adjusts your gallons filled; then the next user gets the updated price.
Also when you enter just those 2 things, it will automatically create a fuel log that calculates things like the total mileage, accurate fuel consumption rating and the total cost for the trip. My wife likes that it has the history of which stations we used last time we were there, so on routes we travel more frequently she always searches for them first... I could open the app right now and tell you those details about every trip for the past 3 or 4 years that I've been using it and it takes me about 30 seconds per fuel stop to have all that.
So, that's why I like it... if you don't use Gasbuddy, what do you use? I'm always open to suggestions if there is something better ...
Brad