Yes I have SM1 in my garage. It's running on single phase with the help VFD for the spindle. It takes a 30 amp circuit to run it.
How big are the parts your looking at making? A small cnc can be built much cheaper than a mill my size. Are you building it because you want to or you doing so that you can make parts? There a lot of work in building a large 12 X54 table size mill.
Do you have a mill to start with? If it's a larger manual mill then your cost will be way more than a new small mill like a X3 would cost.