I'm sorry if I offend anyone but let me just say... Just because you have a digital SLR camera and you take mediocre pictures, does not, by any means, mean you should be charging for your pictures. You should not charge for your pictures until they reach the point where they can compare to professional photography. If you have to give a disclaimer to your clients ahead of time that says, "I'm no professional photographer, but...", I hope your clients run for the hills. You are not worth any price tag if you have to say that.
It is one thing for a friend to thank you for taking their picture by bring you a gift or taking you out to eat, or even giving you a monetary tip. But, you should not be charging anything. Individuals have approached me several times to take pictures for money but I refuse to do it for a fee. I'm not a professional photographer so I will not accept money for it.
I met a woman recently that is charging a sitting fee of $50 for unlimited time and family photos with all of the photos edited. Any person would jump at the opportunity but even $50 would be a waste of money for the quality of photos she produces.
I say, quality over quantity. I'd rather produce 20-25 outstanding images that I would frame and hang on my wall than 450+ mediocre images that no one even has the patience to flip through.
Portrait photography is hard, as I'm discovering from my free sessions. You shouldn't jump into it as a business until you are fully prepared and had plenty of practice.