What are some alternatives?
When comparing PriceDrops and PriceAlarm.net, you can also consider the following products
PriceSpy - PriceSpy helps you save money when shopping online.
Camelcamelcamel - Easily monitor Amazon product prices and get alerts when they drop.
Keepa - Price history charts and the option to be alerted on price drops for all Amazon sites.
Fetchee - Fetchee is a free price tracking wish list app that works with all online stores worldwide.
Savelist - Found products you want but not ready to buy?
Waatcher - Automatically buy on Amazon at your target price