How to find your 'cost' for production?

Good morning, new to the forum. Im on here helping a friend of mine and were trying to figure out how to calculate the costs to make something on his 3D printer. He is using the Alpha Hatchbox to make parts for rc cars.

So example: On Ebay, there is a seller who is selling a small product for $24.99 that go on the feet/corner of something to help stabilize it. Sounds pretty small and simple or very minimal material usage. He also makes controller cases where you can store your controller in and close it, sort of like a glasses case.

But he's trying to figure out how much to charge or what it is costing him PER piece. He said his "spools" run hm $25-$30 each, but like with vinyl printing, it costs $20 some for a roll of vinyl and you have a huge profit margin to work with because material is cheap.

How do you come up with the meter for plastic being used and what not? He was only charging people $5 on Facebook for the same product eBay has for $25 and up.....

Any idea? Thank you

The length of filament used by an object is typically stated by the slicing software used. Some will even calculate the material cost for you if you define the cost per spool. There are also various price estimator tools you can find online by searching for something like "3d print cost estimator".

Not speaking from selling experience, but IMO unless the filament is a special type, on small objects the material cost is going to be almost negligible compared to wanting to recoup the printer cost and wanting some amount of pay for your time and the general hassle of having to process the order. Sellers on eBay/Paypal also have to factor the fees involved in the transaction, which can be hefty percentage on a small item.

So for an example what would something like this in material run?? to make something small like this

http://www.thingiverse.com/thing:1977003

Well, let's see. Loading all 3 parts into Simplify3D that I use as a slicer, configured for three perimeters, three bottom and top layers, and 20% rectilinear infill, the print job would require a total of 6.3 meters of 1.75mm filament. According to Simplify3D, at $30 USD per 1 kg spool, this works out to $0.57 USD total cost for the three.

As I said, pretty much negligible.

EDIT: I didn't include a support structure under the bridge of the rear foot, which might be required to get a decent print that you could sell. Maybe $0.65 is more realistic, lol. Print time would be about an hour at my default print speeds.