I cannot find any web resource for crowdsourced consumer prices - e.g. gas/petrol, water, electricity, and food basics like rice. I am aware of consumer indices such as http://www.fao.org/giews/pricetool/ but its spread for localised ('domestic' category) data (i.e. in towns and cities) is limited, so I'm wondering about crowdsourced data. Anyone aware of anything?
Gas Buddy, the Price of Weed website (SE does not allow a link) and Craigslist all come to mind.
The World Bank did this kind of project in 2012-2013:
The objective of the pilot was to study the feasibility of crowd-sourced price data collection. Non-professional price collectors used personal computers and mobile phones for collecting data and entering it in a multilingual web microsite developed for the pilot. Price data was collected for thirty tightly specified food commodity items on a monthly basis for approximately six months in eight pilot countries. Non-professional price collectors received compensation in the form of airtime rewards.
Seems like just the resource you are asking for