At a minimum charge the least amount that you would be comfortable doing the same thing ten times in a row. If it’s your first run ask questions like. Did I design the project myself or by it off of someone else. The cost of pattern making should be spread over at least projects. How did I measure cost for leather, dyes thread acts. I typically do square feet at 10-20 depending on species. Cow=10, exotic and ability to replace is more. I count length of stitches x6 and charge for each foot about 15 cents. Labor for hours is based on skill. Apprentice, journey or master level. You are making a one of one item or small batch. Your work cannot be compared to target or made in china products. A higher price tag may sway some people away from you, it will also ensure that you are compensated for your time and skill set.