Cheap and free international phone calls, though there are limitations regarding landlines vs mobiles, etc. Still looks like a pretty cool service, if you make a lot of international calls.

Clearance links, filler finders (for when you need to get to $25 to qualify for free shipping), and other tips.

Handy table format for the US, UK, and Canadian Amazon stores, broken down in ten percent increments from 10 - 90%.

A handy guide from Money Magazine