Forget toting around those chunky $30 guidebooks the next time you step off the plane. Download a Lonely Planet City Guide on your iPhone instead, and not only save some money, but save some space while you're at it. Sure $15 is at the top end of what I normally spend for an app, but with all the info you get packed into such a small space (and inside something you're probably already taking with you), it's totally worth it.
You've seen the bulky travel books on the shelves at your local bookstore filled with info on the best places to eat, sleep, and stay (or stay away from) in the city of your choice, but now take all that and add in GPS locational directions, recommendations, and maps so you won't get lost. I'm definitely downloading one for my next trip, and leaving the guidebook at home.