Well after I listed my first few dresses, I quickly realized I would basically be losing money, until I found one website that lets you buy fabric in small amounts! Sew Mama Sew is a GREAT online fabric store! Most others only let you get a half yard at the least.
So I had to do some swap outs here and there and I found some REALLY great new fabrics I had never seen before.
Sadly some of the fabrics I had my eye on just didn't exist outside of the designer's website (who didn't sell it him self, bummer) glad to find that out a head of time though!
There is this fancy tool called the Etsy Fee Calculator that does just that! You fill in the cost of supplies and shipping and it helps you figure a fair price so you can still get a profit. It figures in the fees that Etsy and Paypal take out (which to too much in my opinion).
Thats why my prices differ slightly, I am paying myself the same price per dress plus the cost for supplies!