Here's a snarky, but legal way to save on hotel costs and it comes from a piece on NBCNews.com of all places. In a piece about non-stop travel Mike Hrostoski, the website revealed that he gets some $1800 a year in free hotels from Expedia. How? He games the famous travel site's "Best Price guarantee".
First Hrostoski heads to bestrateguarantee.blogspot.com to find "pricing discrepanies" between online booking engines. When he finds a hotel that's charging less on a site other than Expedia, he makes a reservation for that hotel, then files a complaint about the overcharge, receives a $50 coupon for future bookings and cancels his reservation. He then uses those coupons for free hotel stays.