I've been scouring eBay for key cutting machines for years, but they are a pretty popular item, and were always too expensive. Like starting at about $200 for a decent used one.
Then, back in August, this antique machine came up. I was the only person who bid on it. Got it delivered to my door for $24.03.
It came with this crank handle, but I think a previous owner must have added it. It was impossible to accurately trace the key to be copied while simultaneously hand-cranking.
So, I found this little universal sewing machine motor on AliExpress for $22.01 delivered to my door. I chose this one because it came with the mounting bracket, which I had to alter by bending 90 degrees. The only catch is that all of these various little motors are 220 volt, which is somewhat inconvenient.
The little V-belt also came from AliExpress, for $3.01, delivered. The toggle switch was bought in bulk years ago, probably about $2.50.
So, I'm all-in for less than $50.
So far, I've duplicated one early XS650 key, and it works great.