With more credibility than advertising and much cheaper, public relations is a great value for the small-business marketing dollar. "A few good media placements can launch your organization from oblivion to awareness and help you get clients or raise cash," says independent communications consultant Lilli Cloud, founder of Los Angeles-based Cloud Communications.

While guerrilla efforts are the least expensive way to go, few entrepreneurs have the time or expertise to effectively generate media interest on their own. So, how does a small or midsize firm find the right PR consultant? Cloud, who was a vice-president at PainePR, a midsized firm, and Fleishman-Hillard, one of the world's largest PR agencies, before going out on her own, offers this overview of PR agencies and consultants:

The Big Agency: You may want the credibility and perceived power that comes when you hire the firm that represents IBM (IBM ) or McDonald's (MCD ) , says Cloud. But while some of the best brains in the business work for the big agencies, they may not provide the best value for the small business marketing dollar. First off, your budget must be at least $10,000 or $15,000 a month or the big guys won't even talk to you - but don't take offense. "It may not be the best solution for you anyway," says Cloud. "Do you really want to be the smallest fish in a big pond? The economics of a big agency may mean that you end up getting very little attention."

The Small Agency: With staffs as small as 5 up to about 25, the smaller agencies may be a better bet. But do your homework, Cloud warns. "Often, small agencies are run by one or two experienced professionals with an army of kids right out of college. You may be a bigger fish in this pond, but the itty bitty fish are the ones actually representing you to the media," she says. However, if your product is straightforward and your media targets primarily trade publications, the small agency may get you the results you need and still enable you to stay within your budget.

The Boutique Agency: Firms that lack slathers of international addresses on their letterheads, can still do blue-chip work. Others specialize in specific industries and may be adept at quickly understanding your company. Boutiques often work in complex industries such as technology and healthcare. If you hire one, be sure you are getting strategy along with media pitching. And if you want to move your company's media placements beyond trade publications and into the mainstream, make sure the agency has had success doing this for other clients.

The Independent Consultant: Most independent consultants are big agency drop-outs -- folks who don't want the pressure to bill clients from 7 a.m. to 7 p.m., Cloud says. While some are between jobs and only trying to pay the bills until the next big opportunity comes up, others have gone out on their own because they want more flexibility and are in business for themselves for the long haul. "Many are experienced professionals who formerly held senior-level positions at big agencies or corporations, so you can get the big-agency brains without the big agency price tag," Cloud says. Use the same scrutiny in hiring an independent as you would an agency, she says.

Whichever way you decide to go, be prepared to let your PR agent know in advance what your goals are, how you've handled PR in the past, what materials or news you have already achieved, and your ballpark budget. Find out if the candidate has the experience that matches your needs, and check with their current and former clients to see how they performed. Request a written proposal from the agency or consultant that describes strategies and [plans. This should include an estimate of fees, likely expenses, and what their billing process will be.

Finally, maintaining reasonable expectations is in the nature of the PR business, Cloud says. "Control resides with the editor of the media outlet," she notes. "The agency's job is to make the story as appealing and timely as possible, but if major news breaks on the same day as your story was promised to run, you may get bumped. A good PR person can find ways to retool your story and advise on a better time to approach the media."