Use a better booking engine
Don't use the most famous booking engines; use the ones with the largest selection and lowest rates
It's sad, but the best booking engines can often undersell the rates the hotel itself charges by a good 5% to 15%.
You need to use a true specialist booking engine like Booking.com or Agoda.com—which offer far more types of lodging, including many cheaper ones—or a budget specialist like Hostelworld.com or Hostelz.com (which actually list more inexpensive hotels than they do hostels).
I'm serious. That's why I've partnered with these sites.