My main project in December was Mismi – a service that compares the total price of items from Amazon.com and from Amazon.co.uk for Norwegians. The solution is built on top of the Zend_Service_Amazon class (with a few extensions of my own).
The reasoning behind making the service is that there are several factors that are in play when deciding whether to order a product from the US or from the UK: the exchange rate for GBP and USD, the shipping cost, the delivery situation for the item and whether the item is sold in the store at all.
The user enters a list of the URLs to the products they’re considering purchasing from an Amazon-store, press submit and get a list back of which items are in stock, where the item is the cheapest and what the total sum of an order placed at the store would be. In addition I added a alpha stage feature just before Christmas which will also tell you the “optimum” set of items for the orders – “order item 1,4,7,9 from .com, item 2,3,5,6,8 from .co.uk”. This took quite a bit of hacking – you also have to consider the initial price of shipping, shipping for each item and other fun things.
Feel free to play with it over at mismi.e-mats.org. It’s in Norwegian, but it should be easy to understand anyhow with the description above.