[jegoodwin3]

You should take it a step further and help the retailers add this as a feature to their own apps -- having a store app should include a promise that if the store lowers prices, it will refund the difference for purchases in the last week (or whatever time frame) to loyal customers, perhaps through a store credit. It's a dandy reason to drive adoption of the app.

One thing you should listen to is the number of people who want a reserve price (transaction threshold). This price setting is pure economic gold as information goes -- it tells you their risk aversion (probably) and the shape of their utility curve for extra income. I'm sure it correlates with income, and gives independent verification of income, statistically.

If you have 5 big retailers using your app feature internally, offer to build them a network they can join, to make their rebate offer even more attractive to participants.

With the stores' aid, you can circumvent the problems with email permissions, which frankly are going to limit your adoption. You are far better off working with the stores in a partnership I think, and helping them to understand their own customers' reserve price (and hence propensity for returns and chargebacks, which they surely care about), than being a 'gotcha' adversary.

Added link: https://en.wikipedia.org/wiki/Expected_utility_hypothesis

[austinjp]

Selling this as a service to the merchants seems like a great idea. It would feel less creepy than allowing Yet Another App access to my inbox and credit card details.

Supplying merchants is also likely to provide a more _predictable_ income.

However...

Are giants like Amazon really likely to listen to a pitch from a startup, even one incubated at YC? (No snark, genuine question.)

There is another option: open source the product and give it away, charging for the hosted service. Obviously this may not be an option for Paribus, which would be a shame.