Not to be wet blanket either ...

There are also expenses for packaging supplies and the time it takes to get the kit ready to ship, time and gas to take shipments to the Post Office, time to write and edit the instructions and the plans. Even some expense if you use PayPal. There are shop consumables to consider.

And then there is the time it takes to answer emails. I currently produce a line of scale Mustang exhausts and my email averages over 15 for each kit sold. About half these are from inquiries that don't result in sales. But they all take time to organize in your files.

And then there's the scams to deal with - "where's the kit I paid you for?" and so on. I've had 7 or 8 attempts that I can recall.

My suggestion is to list every expense you can think of no matter how small it seems (including your own time) and then add 30 to 50% to that for contingencies and profit margin. With that kind of thinking you might even make a small profit!

FWIW

Tony Howard
Pacific Scaled Aircraft