your gunna have a hard time selling a full unit, unless its a bargain in price. youll fair better in a part-out.
currently, your system can be built new $1000, used is now $750 in parts and 500-600 as a system possibly. if youll see some other system sales, they too are having a hardish time unless they part it out.
It can be build for ~$700. I'd expect it to go used for 75% of that or ~$500 to the right buyer. $450 is a good deal--you just need to find someone who needs a full build.