The USS-8-64 is a great machine because you can vend just about anything out of it and parts are available in the event that anything goes wrong. It is also a nice compact machine and is easy to move by yourself. My first and everyday user machine is a 64. $450.00 seems high but that machine looks pretty clean. I have seen them go for quite a bit less. Can't hurt to make him an offer or just show up with $300 cash and see if he bites!
Of course, if you really want it go for it.
Tim