First, there's no 'cad cam machine' there is
1 CAD: the software on a PC that you design with.
2 CAM: which tells a machine how to make what you designed
3 a mill or a printer.
If you want a mill, and want it to work for you more than you work on it to keep it doing what it should then you do not want to 'just buy a mill from China'.
You want to spend the time to find out your needs and then what machines fit your needs and then who has the best support for those machines. Then you buy.