I share the point of view of the previous posters. Selling kits or half-assembled units or components on a small scale is not the same as running a business with actual "products".
Also, a small business has some differences to a normal business, I suppose.
Being a "Kleinunternehmer", also, I believe.
Especially in conjunction with taxes.
Someone also can be "selbständig" and/or run an IT bureau (Informatisches Büro etc).
For this, a "Gewerbeanmeldung" might be required.
Also, if someone operates within a school activity or a working group, things may be different also. Depending on the "product", a distributor can also be used to perform the selling. Say, a computer store or a retro-oriented on-line shop. Just keep in mind thst the device must comply to todays standards then. CE sign, lead-free solder, German "manual" (an one-page leaflet will also do) etc etc.
Taxes are mainly relevant in case of profits.
For both practice and intention.
If someone looses money or gains only a tiny bit through the selling, then there's nothing to be worried, because the person in question then effectively doesn't betray/hurt anyone, after all (no bad intention, no profit) . It's mainly important to spend some thoughts on what "business" model fits best before selling anything.
Anyway, I'm just a random person on the www.
I replied here to provide some thoughts that can and should be double-checked.
"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel
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