I got mine from eBag, and you're gonna tear up what you read next: $5, although that was back in 2013...the Campolito shop was really super about this because the eBag buy was just the jig and I was missing the shim set (that's how you set the distance you need to file), they shipped it free of charge!

The Powerhouse company was selling this thing for a while as POW105080, but looking now I haven't been able to find it anywhere.