I've been hunting for a marketing firm. As I've talked with different companies, I've encountered a surprising range of fees. One firm quoted $60 an hour, another over $350.

Consulting companies are much the same. Fees for the same work can run the gamut. So, how can you tell if the fee you are being quoted is fair?

I've narrowed it down to five factors that seem to account for differences in fees. You can use these factors as you shop around to determine whether a particular vendor is charging fairly.

Experience: More experience generally equates to a higher rate. Be careful though. Sometimes more experience just means more years of doing things wrong. Make sure there is a clear link between experience and results before you decide the higher rate is worth paying.

Specialization: Consulting companies tend to charge more if they specialize, because they bring knowledge of that industry to the engagement. This can result in a faster ramp-up time. It can also mean stale ideas. Sometimes it is beneficial to work with a company that doesn't specialize, as they may be able to translate best practices from other industries into breakthrough results.

Firm: Firms tend to charge a higher rate than sole practitioners. This is not just because they have higher overhead expenses. Working with a firm gives you access to the experience and talent of more than one person. Depending on the complexity and importance of your project, paying for this added experience and talent may be worthwhile.

Quality: This is a classic case of you get what you pay for. Only you can decide if quality is worth the cost. Case in point: one of our clients brought us back after working with a less expensive competitor. The issue was poor project management. To this client, it was worth paying extra not to have to manage the project themselves. The opportunity cost of their time and the reduced aggravation was worth more than the additional cost of high quality project management.

Prestige: If you hire a nationally recognized expert or a big consulting firm, you are going to pay a premium. This prestige can rub off on you, increasing your political capital within your organization. It's also harder to get in trouble if you hire a well-known expert. Plus, they may have unique knowledge and experience that can help solve thorny or resistant problems. However, you may get the same or better results on your project by hiring a smaller, lesser-known firm or individual for literally a fraction of the cost.

To compare apples-to-apples, make a chart that lists the consulting companies, their fees, and the five factors above. Place a checkmark under the factors each company brings. This will allow you to put the various rates in context. For example, if you see a high rate, but the company doesn't offer experience, specialization, quality, or prestige, you'll need to investigate further to see why they feel they can charge that rate.

A word of advice: don't fixate only on hourly rate. Look at the cost for the total project. Some consultants who charge a higher hourly rate work more efficiently. This means that the cost of the total project may be less than if you had hired someone who works more slowly but charges a lower hourly rate.

Finally, chemistry counts as much as cost. If you don't click with the consultant, regardless of the cost, you'll be jeopardizing the likelihood of a successful project.