Contracts and negotiated rates:
In travel slump following 9/11 attacks, many hotels dumped distressed inventory on discount travel websites. The rates offered were often lower than negotiated or corporate hotel rates. But for most part, this is no longer case. While it's still wise to check prices on discount hotel booking sites, with fewer unsold rooms, business travelers will increasingly find best deals in rates negotiated by their employers or sponsors of a convention or meeting.

Avoid city centers:
In a city like Chicago, with a good public transit system, I often save money by staying near O'Hare Airport and taking CTA train into Loop. To avoid sticker shock in New York City, I've stayed near LaGuardia or Newark Airports and used public transit to city for meetings. In smaller cities, where parking is less expensive, I find it cheaper to stay in an outlying area and rent a car. With a car you can also avoid being prisoner to overpriced restaurants that take advantage of captive tourists and conventioneers with no wheels.

Corporate apartments and suite hotels:
Such properties frequently offer lower rates than full service hotels which must bear costs of restaurants, bellhops, valet, and many other amenities. A complimentary breakfast and free high speed Internet access can also lower your costs. And with a full kitchen, I purchase groceries and avoid paying restaurant prices for many meals.

Check individual night prices:
Hotel rates vary from day to day depending on supply and demand. But many hotel booking websites are unable or unwilling to display lowest rates each night on a multi-night stay. So I always check prices for individual nights as there could be a savings if you are willing to switch hotels in middle of your stay.

Day trips and red-eyes:
Another way to minimize hotel costs is to take day trips or fly an overnight red-eye flight whenever possible.

Avoid conventions and peak travel periods:
Hotel prices vary greatly depending on what event is taking place in that city during your stay. Don't look for a cheap hotel in Chicago during annual restaurant trade show when rooms are in short supply. But one week on either side can make a huge price difference. I always try to find out what shows are in town before I plan a trip. Holiday periods, like few weeks between Thanksgiving and Christmas, are good times for travel to business destinations, with few conventions or other business travelers on road.

Laundry:
On longer trips I have often saved money by carting my dirty clothes down street to a laundry or drycleaner rather than paying those ridiculous hotel prices.