Oh boxwood, if only everyone knew as little as you do, the world would be much funnier. I'll tell you a secret. The pure material value in a car is probably about 10%. But such a press costs tens of millions. And since it's hard to work in rain and snow, a hall must be built around the press. And a road so the workers can get there. And, and, and. The clever car manufacturer includes all that in the car price, after all, he doesn't do it for his own amusement but because he wants to make money... and the employees do too, by the way. The calculation material price + the 2 people who put the stuff on the roof in 20 minutes is already too naive even for my 6-year-old daughter...
He wouldn't be the first to spend the rest of his life in a wheelchair or drooling in bed because he wanted to save a thousand bucks and climbed onto the roof himself. Just the scaffolding that the ambitious hobby handyman has to rent to mess around up there for a week easily costs 1,500 EUR.
What technical products do you sell that you know so little about the matter? AA batteries?