Here is the template I use to price out my 3D Print Jobs.
The metrics that work for you will depend on your business.
I am primarily doing high volume prints with very simple filaments and settings so I am for a minimum of 40% Gross Profit and $2 in profit per print hour.
BUT
If I was doing smaller quantities or unique projects, or specialty materials I would be charging a lot more. Probably between $5-$10 in profit per print hour.