Putting a Price on my Cards

One thing I find most difficult is to put a price on my cards. I “think” I need to charge by size 4×4 or 5×5 or regular card size. The thing is that I make the “paperscapes” first and they all take the same amount of time. I have just spent a month making cards (pretty regularly) and have made about 50 cards give or take a few.
Putting a price on any type of art is difficult however I seem to be able to do that with a painting – yet I get stuck with the cards.
The blank cards cost me about the same, now adding a label and cello cover all costs money, I have been through 6 glue sticks !!! Big Ones !!
I guess what I am processing here is that I am going to put a price on my cards this week and stick to those prices……..by size or by card is my dilemma.
and if that is the only dilemma in my life I AM BLESSED !!!!!!