Camelcamelcamel - Easily monitor Amazon product prices and get alerts when they drop.

Repricer - Repricer.com is your one-stop pricing hub. Sync your entire inventory and automatically manage prices to achieve consistent pricing across channels or create rules to price higher or lower on some channels.

Fetchee - Fetchee is a free price tracking wish list app that works with all online stores worldwide.

Minderest - Leading price intelligence and competitor monitoring tool for retailers and manufacturers. Learn your competitors pricing strategies and increase your profits

Keepa - Price history charts and the option to be alerted on price drops for all Amazon sites.

Listinguish - Listinguish, the easiest way to increase your e-commerce sales.