I typically charge $55 to $100 per hour based on the expertise and research required for any given project. However, what I like to do is meet with a prospective client, learn all I can about the proposed assignment, and prepare a flat fee proposal that details the project activities, outcomes, and deadlines. You’ll know the total amount to be charged and I will know what I’m being paid!
Sometimes a project will take many months to be completed. In that case, we will work out as we move along. Communication will continue throughout the project and you can expect regular reports and opportunities to review the materials as developed.
Multiple changes in the specifications? We’ll have that discussion when the time comes.
In relation to article assignments for publications, I understand that there are set fees and happily work within the payment schedules as determined by the publisher.