If a field or 2 were added to fuel ups it would be possible to map price of fuel ups per country/state/county/area/shop.
There are already some sites that allow users to edit price of fuel at specific locations. This is referenced by other users so they can get fuel at cheapest location. It might be outside of what Fuelly wants to do but perhaps a link up with a fuel price tracking website would be a good way forward.
Yeah, I think there are some sites that already do this very well. GasBuddy is the main one for the US. I've seen one for the UK, but I can't remember it offhand.
On Fuelly Mobile for the iPhone, we even gather a longitude/latitude when you fuel-up (if you approve it), but we haven't found a good way to map those coordinates to gas stations. We recently talked about it here: Location Awareness. So with location-aware phones you wouldn't even need the extra form fields if you could look up business names by lon/lat.
I think it'd be interesting to partner with someone like GasBuddy. They ask their members to report prices, and Fuelly members are already putting prices in for their own reporting. They could increase their reporting numbers if we could find a way to connect the systems. I'm not sure what Fuelly members would get in return but it seems like there's some sort of cross-pollination that could happen.
I used to use the iPhone app GasBag to track my fuel ups, it used location services to find local stations, you could then select a station from a list or enter your own if it didn't exist (kinda how foursquare works) Of course it was so limiting on other options I've since switched to Fuelly.
Would it be possible to simply allow users to create their own listings similar to how you do on foursquare, then when you use your location you could select the station you want to use. Maybe even adding an option for a "Favorite Station" would help so it would automatically select a station if you were within x distance from it, as it seems there are always 4 or 5 gas stations next to each other. Of course you could manually override that option. (i.e. I tend to fill up at a BP that is next to a Marathon, if for some reason I went to Marathon (huge gas sale??) I could just select the station and override my automatic input)