I happened on some really useful information today that I would like to share. The original source is here:
http://www.consultantjournal.com/blog/setting-consulting-fee-rates
Setting consulting fees is a challenge for independent consultants. There are many ways to determine what to charge like asking others or calling for quotes. Past experience also is useful.
The site listed above suggests several models for a fee structure and determining the rates. Techniques like doubling or tripling your hourly rate are common.
How does one determine what hourly rate to charge to begin with?
One guideline I use is, what are you willing to accept to do the work? Your expertise has value and you are not expected to give it away. Circumstances may lead you to accept a lower rate than what you feel the market is at but most consultants have been there...
To determine what your hourly rate should be, you need to know what your expenses are. These make up your overhead and need to be considered when setting a rate.
For more specifics on implementing fee structures and models, refer to the link above. The site author talks about these techniques and much more on her site.
As a consultant, I find myself faced with these challenges frequently and look to model sources for information.