As a bit of business advice that I'm about to give you, I need to preface it with a very basic term that most people seem to forget: Critique is there to help a person grow as an illustrator. It is not there to tear down someone.

That being said, I do not believe the prices you have are worth the quality you are providing.
Taking your price tag into range, and searching FA for equatable individuals charging similar amounts, I have found that there are others out there who are able to produce illustrations at a higher level than you for the same amount, if in some cases less.

Some examples are as follows:
http://www.furaffinity.net/view/20439227/

http://www.furaffinity.net/view/20440242/

http://www.furaffinity.net/view/20442698/


I would like to say that should you provide your price range with a more cost-effective mindset, you would need to focus upon the three primary points: Perspective, Anatomy, and Color Theory.
With these three techinques firmly in grasp, I have little doubt you could attack creations worthy of your asking price.