The idea seems great. But my spidey sense is going crazy. You want access to my financial/purchase data, and the service is free. So you will monetize ..... how?

I am 100% not saying you intend to scam or steal. But clearly access to my data is key to your eventual monetization plan, and this is a loss leader to get in the door. Since the ultimate plan is not stated, I have no choice but to imagine it, and nothing I can think of warms my heart.

The ability to feed your service with something like a periodic manual export from Mint (assuming such a thing is possible) would go a long way toward reassuring me.

Again, the core idea seems fantastic, and could save many people real money, including myself.