I have bought machines on ebay. One in particular was a Singer 99 in a bentwood case. It was poorly packed and arrived damaged. The case itself was damaged, and the machine was not working. I ended up replacing the needle bar and painting the machine. It works now.
I did notify the seller, telling him that I could not leave positive feedback because of how the machine arrived. He did not respond.
The last machine from ebay was an early birthday present from DH. It arrived very well packed with no damage.