How much is a colored pencil drawing worth to you?

I have always debated myself on this question, how much is a colored pencil drawing worth?  I cannot find any real source of information on how much colored pencil drawings should sell for.  I have been lucky enough to sell some of my works, but most are to family or to friends of a member of my family.  So I am not sure if that is a legitimate scale to go off of or not.  

Does one price pieces according to how good they are?  If one is better than the one before it that sold for a lot, should that one be more?  Or do you just sell it for bottom dollar prices just so you can make more and get rid of the old ones?

I have been blessed enough to sell four of my drawings as some may already know.  I sold one for $295 at a church charity auction, I sold another similar one at $370  with the frame the next year from the person that did not get the one from the auction the year before.  Then I sold two different ones individually to a family friend for $80 and $200 respectively.  That is about it.  

So what is your opinion, how should colored pencil drawings be priced?  Because no offense to painters, but painters of portraits, that are more abstract and not as good technically go for hundreds or even thousands of dollars, and I have the poor of that.  Or does one just have to accept that colored pencil work is considered less professional and more amateur and just take the hit and keep the price in the low hundreds if that and be happy at that.