Jungle Scout - Amazon product research made easy.
Camelcamelcamel - Easily monitor Amazon product prices and get alerts when they drop.
A2X - A2X automates ecommerce accounting for Shopify, Amazon, Etsy, Walmart and eBay sellers worldwide. Trusted by hundreds of leading ecommerce accounting firms.
Keepa - Price history charts and the option to be alerted on price drops for all Amazon sites.
Helium 10 - Our software contains multiple Amazon seller tools to help you find high ranking keywords, identify trends, spy on competitors, & optimize product listings.
PriceSpy - PriceSpy helps you save money when shopping online.