If you still have gift cards left over from the holidays with no idea what to spend them on, search engine What Can I Get with $20 can help you decide, searching a category of the Amazon store by price.
To search, just replace the "$20" at the top of the page with a number of your choosing. Pick a category from the drop-down menu and then hit search. The engine will give you a list of things near that price range, that you can then click on to buy from Amazon.
The categories can be rather broad—there are a lot of iPad cases or netbook bags under "apparel", for example—but it's a pretty cool idea if you have a $20 Amazon gift card and have no idea what to spend it on. A simple search-by-price can inspire you. Maybe you realize you need an iPad case, then you can head to Amazon and do a more narrow search for iPad cases. Hit the link to check it out.