You can save at least 5% and easily as much as 15% on most things you can get at Amazon.com if you buy them through Purse. You don't need to get Amazon Prime, yet you get almost as fast shipping.
Purse is a service that lets you put orders up for bidding. People who have Amazon credits that they can't use for themselves will buy your order for you. They use their credits, and get paid in bitcoin. This works for them because they might not be able to spend their Amazon credits due to their country's laws, for example, yet they can earn Amazon credits.