This and your other posts seem to point toward a tendency to put the horse before the cart. In any pricing point determination, you need to first figure out if your product has monetary value in the market you seek to enter. There is no easy route here, you do that by researching your market, looking at other photography offerings in your area and doing a realistic comparison of your product offering vs your competitors. Can you offer the same or better quality of product. What services do they offer, identify those you can/can not offer. Is there a niche not being serviced. Is the market oversold. What price point would you have to be at to woo customers away from established businesses. Only once you've narrowed down the market parameters can you start to look at price.
The advice given already, can establish a range to be at to make a profit, but it's simplicity is also it's limitation in a real world dynamic market. A customer doesn't care if your COGS is $X, especially as a new kid on the block. The customer will go with the one who they perceive to have the better value for dollar spent. I can also guarantee that those who've been in business for awhile have learned efficiencies and vendor selections that allowed them to reduce their COGS. Here's a link to a simple discussion of pricing strategies I used for years in my businesses.
Pricing Strategies bear in mind these are simple explanations and would require more study on your part. I could literally write a book on each of them after 40 plus years.
In any market transaction there has to be a seller willing to sell at a specified price and a buyer willing to buy at that price. The successful entrepreneurs are those which can arrive at that exact point so as to maximize profits, but not exceed such that buyers are unwilling to pay.