I just booked a hotel room with Booking.com, an app on my iPhone. Within 40 minutes I found a better deal elsewhere and with another app. When I tried canceling, their site clearly stated they won't charge me if I'm canceling before arrival. I proceeded to cancel within 40 minutes of booking. I was shocked to see they charged me a cancellation fee of $ 129! I wouldn't recommend them to anyone and never ever give your credit card as security. I did it because I had honest intentions, they took it for other intentions. There's no reason to give a credit card number. This is truly a first rate rip off, my advice, take the time and deal with the hotel directly, it may cost slightly more, but it's worth it in the end, they won't hit you up for $ 129!