I make a lot of Amazon purchases. I thought Paribus would be a great app to get the best price available, but when it scanned my email, first it took for ever. Secondly it only picked up very recent purchases. And lastly when it did get the price change for one of my purchases it never got me the refund. I sat there for 10 days looking at a lower price and it did absolutely nothing.
Dr_Proctor about Paribus: Money Back Shopping, v2.2.0