Well, many of my cels are marked NFS ... and I 
wouldn't outright sell any of them. The best way 
I have found to attempt to get a cel someone has 
marked NFS is to make a trade offer. In general 
with me (unless I've just spent a huge amount of 
money on cels...and even then it usually doesn't 
matter), a cash offer does not sway me. However, 
I do have a couple of cels that I would consider 
trading if something I was really looking for was 
placed in front of me. :)

I do have 4-5 that I will never let go of for any 
trade or cash offer. ^^

Sheri