Charles,
You raise an interesting question here for me, but not the one you posited. I will also supply an answer to what you have here, but first:
I have no way of knowing how you came to work for the company you are with, but since I run an agency, I want to suggest that if you are taking on clients that could be going to your agency, whether or not you believe they are a good fit, you need get approval from the agency. You state:
"I'm looking to take on a few more clients and have built a nice local reputation so I have a few different people approaching me, **right here, my question is, how did you come by this reputation? Before you went to work for the firm you are with or while with them? **normally I'd pass them on to my boss but there are a few clients I would rather keep to myself as I don't think they'd be a good fit for my agencies model." **When you do this work, do you use any of the agencies tools? Say they have software licenses that you have access to, are you using that software to assist in what you are doing? **
To me, this is not even a gray area, but black and white. You are performing services it appears your agency performs or close enough that you make the statement they are not a good fit for an agency model.
To me, this is the bigger issue than fees. Short of that, how you charge is very nuanced to individual situations. For me, we started out several years ago much lower than I wish we had. Today, we are much more expensive because we have learned that nothing is as easy as it seems or as the client lays it out to be. My favorite example of this is the ecommerce site we took over and rebuilt. The only thing that had been left out of the original equation was that they had never had a sale. Yes, I wish I had charged more now. But, for link building, content, etc. you need to set reasonable expectations and charge to achieve them. We charge between US $75 and $200 per page depending on the content type and amount. For link building, a complex site will be thousands of dollars per month and we try to be very clear about expectations.
Lastly, I have allowed our people to occasionally take on a freelance gig. On one or two occasions, I sent prospective clients to one of our people to handle as I knew they could not afford us. One of them is now a client since that individual did a good job. When they needed a site, they came to us.
I hope all of this was helpful,
Robert