[Detect]

> How do you get reliable data?

Use a trusted third party API like Good Guide or Environmental Working Group (EWG), which contains data on about a combined 300,000 products.

> How will you make money?

Allow users to optionally tip (defaulted to 10%) an additional portion of their donation to TrueCost.

> Do people actually care about the environmental impact of their purchases, or is it just social signaling? Could you capitalize on signaling with social media sharing of "I just offset the environmental impact of [my purchase] with TrueCost!".

70% of US consumers are concerned about environmental impact of their purchases sometimes, regularly, or every time they shop. Source: Cone Communications

There is definitely an opportunity to leverage social behavior to drive awareness and referral.