I've had the chance to know Matty Morgs for a couple years now. He is a very talented designer and he's learned a lot in design and the business side of things since I first met him. Matt offers some great insight and ideas for all clients and he doesn't disappoint below. Be sure to check out his WEBSITE
*Be sure to check out a couple pieces of his work below too.
INFLUENCING FACTORS: Understanding Pricing In The Design Industry
Your Clients Deserve To Know
The development of creative technologies we are seeing in our time undoubtedly brings on a consistent flow of new possibilities in the world of design. With the ability we now possess to collectively piece things together (and just as quickly tear it all apart), all sorts of new expressions and opportunities have emerged. As creative people, we prefer not to nail things down - Can you really blame us for not wanting to put a limit on "what could be?"
The industry, by that nature, is continually changing and quite progressive. And while this allows for much innovation, when it comes to doing business, foundations need to be laid and there are certain things that just have to be nailed down. Without doing so, prices seem rather subjective making it quite difficult for a client to know what they’re getting into. And as you provide a service, your clients will appreciate you for being honest and upfront about what it takes rather than masking your process in obscurity.
Essentially there are a few key factors which influence my pricing. Factors I believe the client deserves to know. Below, I have listed the key factors I use to let my clients in on the process and help them to understand why we charge what we do:

Current trends in the industry.
It is good to know what else is available to your client.

Ability & experience of the designer.

Position yourself vs. what is out there.Once you decide where you fit in that bracket by gauging your abilities and industry experience (business knowledge and your ability to work with clients is just as important as skill).
With the above two considered, I am able to develop a list of standard rates which I then adjust higher or lower based on the follow 3 categories.

The originality of thought, expression & imagination.

What is the client asking for? Will this demand a lot of mental energy or is it simple to produce? Does it give off a really fresh vibe or is it as 'fresh' the sushi at the grocery store?

Turnaround alloted for & estimated hours from conception to completion.
What kind of deadlines is the client looking at? Is it a rush job or do you have ample time? And most importantly, how long is the thing going to take?
Nature of the final product and how it will be used.

Let's use a t-shirt as an example - if the client will be making money from your work, you should be charging more.
And when it comes to a logo/brand, this is worth more than the basic design as this will become your client's identity which will be used on stacks of product and communication pieces.
*Don't give away your source files - The client is paying for a finished piece, if they want to take your work and turn it into anything they want, they should be paying for it.

Quality, creativity and the unique requests of the client all get factored in to the going rate and we arrive at our quote.
May you and your clients stand on solid ground.