Which is the best website for budget hotel booking/ comparing room ...

China Airlines, EVA Air are the airlines I fly the most but, with the fuel surcharge I booked Thai Airways direct flight being only a few dollars more, more like USD 50 more but, it is a 17 hour direct flight. The assumption is that you are flying .... EVERY HOTEL IN THE CITY IS BOOKED FOR THE DATES I NEED? IF I BUILD A TRAVEL WEBSITE HOW DO I GET MY SITE TO COMMUNICATE WITH A HOTEL RESERVATION SYSTEM TO BOOK ROOMS? HOW OLD DO YOU HAVE TO BE TO BOOK A HOTEL IN MONTREAL? ...