I built one for my 4016. There's a lot of pieces and a lot of drilling. I started by cutting, drilling, and bending, all of the parts.
Then I welded it together and did a test fit on the tractor.
Then removed it from the tractor and painted.
When I was all done, here's how it looked on the tractor.
As for cost, I'd break it down like this:
Most of the steel I had except for the round bar and the sleeving:
we'll say $20
4ea Category 0 weldable ends: $35.42
Hydraulic cylinder: $115.00
2ea Adjustable arm links: $84.70
2ea hydraulic hoses @ NAPA $90
Adjustable top link $25
pins, and hardware $25
What I can't count is numerous hours ~20+
and paint plus all the steel that I had on hand.