You are right about that guys, I too have to lower the cost of some parts if my wife happens to ask it

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You might thing that when you build something from scratch it's much cheaper, but if you count even some amount per hour, you'll end up high numbers.
So it's very difficult to give any estimate of what these things cost. I'm thinking that this is a hobby that I like and if somebody is ready to pay you some money of something you build that's a bonus