well skygazer, the only sg around here is solar guppy who owns this forum. i'm just kidding you so unclench your fist.
as to the inverter, i say make the guy an offer. it has been outdated and upgraded to other inverters, but if new in the box it should work for many years. this forum does address some of the ins and outs of that inverter and any quarks with it so read up on it before you decide.
as to this and other used inverters, i don't hear of too many that are of quality or in good condition that often. i suppose ebay may have the most listings of such equipment and you should try to know which are in current production or not as parts may be non existent or scarce with a premium price tag.