Well, he hadn't graduated high school yet. Your points about the expense are probably sound, unless he was doing some serious wheeling and dealing (which is certainly possible, some high schoolers flip sports cars and make money that way, etc) but a large part of that would be an artifact of being one of the first to attempt this sort of thing at this scale. Modern manufacturing often doesn't scale down very well. Such steps are necessary, however, to improve the level of capability of the hobby community in general. The next project will probably be done cheaper, learning where there is flex in the process, etc.