to IIS Ian,
A 10 inch dob for $450 may be good value, but if you have no way of checking it's condition then you are probably better off dealing with someone like
Bintel or
Andrews communications. Bintel, for example offer a 10 inch premium dob (includes cooling fan and crayford focusser) for $679 new, bundled with 3 EP's and a moon filter, IMO a safer proposition than a second hand ebay item and within driving distance from your location (no risky freight).