Hey, if you know someone traveling on a budget to Europe in the near future, Amazon offers some Kindle books for free for a limited time - and this time it's the Let's Go Europe 2011 book for students traveling on a budget, normally $21.95 for the paperback.
Even if you don't have a Kindle, you can download it to your laptop, and read it using the Kindle app for Windows and Mac. You can even get it on an iPhone or iPod Touch, smartphone or other handheld device that uses the Kindle application. It could be a handy online reference for a future trip, and unlike many phone apps it does not require an always on wifi connection!
I've been advised in the past to avoid the Let's Go series, whose destinations are well-worn, but hey, the price is right, and might help in a pinch when looking for cheap lodging, cheap eats, etc.
Enjoy!