Just choose the city you are traveling to and the beginning and end dates of your stay - the app does the rest. Within seconds, you'll see the best prices shown for whatever you're looking for.
When searching, of course, you can also filter the results based on available services. For example, you can look for only hotels with wifi, a spa, or any other services you might want.
Trivago is a must-have if you travel and want to get the biggest bang for your buck; according to its website, the average savings for users of this app is 32%. It's worth a look.