AmzScope - Find profitable products for sale on Amazon in one click, relying on statistics instead of intuition
Camelcamelcamel - Easily monitor Amazon product prices and get alerts when they drop.
AMZScout - AMZScout extension will help you make a decision about picking a niche based on the actual data, not intuition.
PriceSpy - PriceSpy helps you save money when shopping online.
Jungle Scout - Amazon product research made easy.
Savelist - Found products you want but not ready to buy?