But getting the best price on a hotel room is not just a matter of going to the best websites. As a travel expert, Diener has some great ideas for booking a bargain on your own. One suggestion is to join the hotel's frequent stay program. It's free and could mean a room upgrade at check-in, plus a late check out.
"A lot of times you will get a late check out at 4 p.m. instead of the typical 11 a.m. Some will give you free gym use, some will give you free papers, some will give you free breakfast in the morning. These really add up and it is absolutely free," said Diener.
Another suggestion is to stay more than two nights in a hotel. Diener says you could get anywhere from a 5 to 40 percent discount off the entire stay.
"If it's 40 percent, not only are you getting the third night for free [but] your other nights may be less," he said.
And don't forget to use your Auto Club Card. A lot of roadside-type hotels offer special rates for AAA members.
If you're planning a trip to Europe, don't be misled by the hotel's rating.
"European standards for ratings are very different than the U.S. They're typically much lower so you never want to rely on a European rating of the quality of a hotel," said Diener.