I received these KSC-50's a couple days ago, but found that I don't actually like walking around with earclips on. They remind me too much of my old job, answering phones with an earclip phone attachment *shudder*. They are basically in new condition, and I still have the packaging. I've burned them in for about 10 hours, and have taken them outside just once. You wouldn't even be able to tell that they have been opened. I'm putting them up for $15, SHIPPED.
I'm also willing to consider a trade for Senn. MX500.