I was always curious about the locking mechanism that holds the shackle.
The shackle is notched, and the back end of the plug is also notched to hold the shackle closed when locked. As you turn the key clockwise, the end of the plug will rotate disengaging from the shackle, and it will open.
Very similar to the mechanisms on bycycle locks like the large Kryptonite U locks.
How much it is?
No idea. It was a gift.