Idea - good or bad?

Personalized CPI tracker based on your past Amazon purchases.

- scrape / or request data from Amazon order history
- look up today's price of the products (if the very same ones still exist!)
- calculate the inflation

Would you expect it to be useful given the caveat of dropping the missing data and no (hedonic) adjustments? 

 I don’t wanna call it good or bad, but it’s really interesting. 

Another thing to factor though is what were you planning on purchasing but didn’t.   One good example is a Home, for many … CPI through the roof on that one. 

 Good point. I expect real estate would be a whole level up. This one would be just a personalized consumer goods category.

Maybe if crowdsourced, then you can get a public datasets of prices od many goods over the time, that would be some cool hard data to have access to for anyone.