Camelcamelcamel - Easily monitor Amazon product prices and get alerts when they drop.
wwwant - With Ant.com, search the web has never been so simple. Ant.com gives you the possibility to bookmark all your favorite webpages and access them wherever you are.
Keepa - Price history charts and the option to be alerted on price drops for all Amazon sites.
Wishtack - Create your wishlist right now!
PriceSpy - PriceSpy helps you save money when shopping online.
WishSimply - Wishsimply is a easy-to-use online and mobile service to manage and share your wish lists.