Rule #2: It takes lots of cash to stay in stock.
After I built the button, I got an email from a guy asking if I could build one for him, and I did. At the time I didn’t follow the pricing rule of 2.3x and didn’t account for shipping (but I also didn’t do the programming, as he wanted to do that.) In the end, after I charged too little, and didn’t account for shipping, I ended up making so little money that I was getting paid minimum wage (or less) for the work I did. As a one-off thing, this isn’t too bad, as it was an interesting experience, but as a business it would be a complete failure.
So I’ve already established a price, and now I need to actually have items to sell. I’m starting with just 10 units. I’ve ordered the parts (from 4 different companies) and when everything gets here, I’ll do the soldering, programming, painting, and assembly, and then have 10 units to sell. (And yes, I did factor in the shipping costs I paid into the price I need to charge.) If I can sell 4 units, that will cover the costs of the materials, though not the cost of my time. I’m assuming right now that if I sell all 10 units, I will have covered my costs, and actually be able to cover my time at a reasonable rate. (That’s the theory anyway.)
I really don’t anticipate needing a huge amount of stock. I mean, demand isn’t overwhelming (yet) for what I am selling, and if I run out, well, I can choose to make more (or not) and it shouldn’t affect my overall business too much. It might annoy people if I’m out of stock, but hey, that’s all a part of selling physical goods, right?