The World Bank provides data, but it is aggregated on the yearly level. Their source is German Agency for International Cooperation (GIZ).
Pump price for gasoline (US$ per liter)
Fuel prices refer to the pump prices of the most widely sold grade of gasoline. Prices have been converted from the local currency to U.S. dollars.
There is a download button for XML, CSV, or Excel.
World Bank Data License
You are encouraged to use the Datasets to benefit yourself and others in creative ways. You may extract, download, and make copies of the information contained in the Datasets, and you may share that information with third parties. You may also use our application programming interfaces (“APIs”) to facilitate access to the Datasets, whether through a separate Web site or through another type of software application. However, we maintain a list of some specific data within the Datasets that you may not redistribute or reuse without first contacting the original content provider(s), as well as information regarding how to contact the original content provider(s).
(handful of datasets have different license)