@kkirk001 Marantz is one of my favorite brands that I highly recommend. If you want to negotiate with the buyer I think that's okay. Many people will initially offer a lower number than they're willing to accept in case the seller says yes.
If you counter and the buyer is really interested they will reply and say they can't do more than $350 at which case you can still say okay.
If you counter and the buyer is not serious then they probably won't even bother to reply, in which case then they may not have been a great person to do business with anyway.
You could also try asking to discuss further on the phone. If the buyer is willing to share their phone number and talk then they're more likely to be a serious buyer and you can try to figure out a price that works for both of you.
If you counter and the buyer is really interested they will reply and say they can't do more than $350 at which case you can still say okay.
If you counter and the buyer is not serious then they probably won't even bother to reply, in which case then they may not have been a great person to do business with anyway.
You could also try asking to discuss further on the phone. If the buyer is willing to share their phone number and talk then they're more likely to be a serious buyer and you can try to figure out a price that works for both of you.