I think that, if you charge all the hours, energy and materials you will come up with a price that will not bring you any orders.
It also depends if you do this “on the side” or as a business. It is somehow also a bit of love for 3D printing. If you enjoy doing it you will settle for a lower price which is also affordable.
The other thing is something like a “fair” price; in other words: what would you pay for it yourself?!
At the moment I am charging € 6,00 per print and € 0,35 per cubic cm, which I believe is a fair price and sometimes even a little bit to fair. It would be nice to be able to differ between small and large prints and whether you can print the order in one print run or more.
Goodluck with your presentation (if I am not to late) !
Kind regards, Guy