Domcomp - No-nonsense domain price comparisons, updated daily
PriceCute - Keep up with your competition's pricing on Amazon
dofo.com - Domain search platform Dofo.com gathers all registered (350 million) domains of the world in a single place. Dofo also brings together all the domain names that are on sale, provides useful features, all completely free.
Yellowbag - Save your favorite products and buy when the price drops
Pricepeek - Compare prices of the same product across all Amazon locales
Camelcamelcamel - Easily monitor Amazon product prices and get alerts when they drop.