How u price digitizing

I now charge flat 10 usd per design, may be due to slow market
But question is how u price, based on complexity or stiches

Location: 
United States

Steve
Embroidery Digitizier and Color Separation
20 Years Experience
(Price : 10 USD Flat OR 1.5 USD/1000 Stitches)
First Two designs Free to Try
gnizitigid@gmail.com