I would not sell for anything under low $xxxx to anyone. If anything, 3 letter domains (especially good acronym candidates such as SNG) are worth holding out for end users.
As an example, we've held RTM.us for several years. While it was initially used as a divisional site for our US offices, we decided to consolidate on our primary domain. That said, we turned down offers of $1500-2000 from 5 end users, while the highest reseller offer we got was $800.
I would definitely hold on to sng.net through the economic recovery which is already happening (perhaps not quite yet in the US, but soon enough) and then courteously approach suitable end users.
Good luck with it.
Rob