HA!
Fohat, when I was young, I loved the piano and considered being a music teacher.
You don't call music Content. Not even if I was the one playing it. (I'm only a barely competent pianist, and I still find it offensive to call my playing Content.)
Content is only used by business people, studio executives and other non-musicians.
This is the difference between somebody out for profit, and somebody who's dedicated to his art. I won't low-ball an artist because it's mean, but if someone is doing a business, then he's got to be thick skinned and endure tough bargaining.
You can probably pay somebody in China or some other low-wage countries to bolt-mod your keyboard for $20. Together with materials, it should be under $50.
For a craftsman, I have no idea of the real value, but it definitely is far, far higher.
So is that a product or a piece of craftsmanship? That's an interesting issue, isn't it? A craftsman deserves geekhack prices. A producer should compete with generic products from China, including bolt modded keyboards should they ever be listed on Taobao.
I can assure you, that outside Geekhack, people won't pay anything for mechanical keyboards. Talking to some people who don't appreciate such things, they estimate things like $20 for the value of a Model F "because it is heavy and there is lots of metal" and $2 for a blue switch Filco "because it is noisier than a rubber dome worth $10". A Click-Clack "looks like one of those Chinese toys you can get from a kiddie vending machine" so it's worth $0.50. A full set of Topre blank keycaps are worth $0 because they are "flawed, you can't see anything; factory forgot to print legends and you can't put them into the recycling bin because they are plastic".
A craftsman doesn't make Products.
What are you going on about.
What else do you call something that someone produced?
True, the word is rather generic, like referring to music as "content" but it is the least common denominator.
Realistically, I think that this seller would need to get somewhere in the mid-high-$100 range to make the enterprise viable. It looks like he has a number of these to sell, and I recommend that anyone who wants a really spectacular Model M buy one from him while they are available.
I have probably done around a dozen M bolt-mods, and it is always harder and more tedious than you would imagine. I would guess that there will always be multiple hours involved in each one, along with a non-trivial supply of parts.