How Much Should I Charge
This is mostly my opinion.
Probably more than you think and probably more than a lot of people want to pay.
There are two prices. One is how much you should charge family/friends and the other is how much you should change if it is a business. I print for family/friends and give them the stuff. Printing is a hobby and I enjoy it. If someone asks for a lot or something I don’t enjoy, I can say no. If I started charging it would not be a hobby and I would not enjoy it, so it would be a business. If I were to have a business 3D printing I would give a discount to friends/family, but it is a business and I would treat it like any other business.
Let’s start with the easy stuff. The slicer will tell you how much plastic, If the thing takes 10 grams of plastic and you get PLA for $12 a kilogram that’s 12 cents. I would at least double the cost of plastic, the print will occasionally screw up and you need to print again, plus you buy the plastic wholesale and sell it retail, plus you have inventory. Yeah, double may not be enough.
The slicer also tells you how long it takes. The electricity is so small it’s not worth figuring it out. The printer, you bought it and you have to maintain it. Charge a portion of that. Maintenance includes the parts you have to replace plus the time of a trained technician, you, to replace them. Look at what you do, get a cost for your time, the time of a trained technician. You will be surprised at how much that is.
Toss in a flat fee. This includes incidentals, like the electricity, rent for the space the printer takes up, and a bunch more. A real business may have a better idea, they may pay rent on a space so they can divide that by the number of printers they have.
Now a harder part. How much work are you going to put into the object. It needs some supports, it takes a while to get them off, after you get the supports off are you going to clean up the print where the supports were? Do you go beyond minor cleanup? Are you going to spend hours finishing and painting? It could take a couple minutes to snap the support off a helmet, or it could take weeks to snap the supports off, sand it smooth, fill it, sand again, fill again, sand again, paint.
Is it a unique print with a fair amount of prep figuring out the best orientation or just one of the things you churn out every day. The time for a person who has spent years learning the ins and outs of 3D printing should get paid as a professional. An independent technician with training makes a lot more than you get paid since he has a lot more costs than you. An independent contractor has a lot of other expenses. How deep do you want to go down that rabbit hole?
Look at how much a business would charge. I saw a bunch of posts of the type this is a simple print and Shapeways wants to charge __ for it, that’s too much. Shapeways went bankrupt charging ___ for a print. If someone says you are too expensive and it should only cost __. You need to subtract __ from what you wanted to charge and decide if you would give that much cash to the person. If it’s too much tell them no. Most people would not walk into a store, owned by a stranger, look at a $100 item and say “that’s too expensive, how about $30”. They have no problem talking to a friend who says it cost $100 and saying the same thing.
You provide a service, it has a price, give friends/family a break, if they don’t want to pay they don’t get the item.