How can you buy potatoes online for a 49 year old housewife in Ajmer? An app can change such a consumer’s well-grounded habits in two ways – offer him ridiculously low prices, way out of the local grocer’s league; Or ask an agreeable person in your circle to sell potatoes and assuage his fear of buying online. Community shopping has some of these two options, a concept popularized in China by Pinduoduo, now taking root.