Sounds pretty simple (but it is). I go to hotels.com and see what's available for my price (plus I can check out if the hotel has good private parking etc.). Another good site is lastminute.com It's a British site, but I got a 4 star hotel for my wife and I for about $100 a night. Came with breakfast and everything. Only catch is you literally have to do it at the last minute (2 or 3 days before). Kind of hard if you are living in the U.S., but no big deal if you are in Amsterdam.

Enjoy!