From the Forum

Updating Gas Prices:

In the US:
* We get new prices update automatically once a day, but we still rely on the community to keep them updated, as gas prices change frequently.

In all other countries of the world:
* In most countries the gas price feature isn't available yet, as we're waiting to have a good coverage of the gas stations before starting the service.
* We will slowly add this feature to more and more countries as we feel the coverage there is sufficient. As mentioned before, we're working on adding a full list of gas stations to a few countries, and hopefully we will have the gas price feature in your country in the near future too!