For the most part, I am not all that worried about barter after a TEOTWAWKI type event. No matter what you have, getting good value for your stuff is going to require widespread knowledge of just what you have and I think a much lower profile is in order.

I also think the idea of bartering services for hard goods is probably more fantasy then reality. I often see people suggesting they would be able to barter their service as security guards or first aid suppliers. Really? Those kind of skills are very widespread in varying degrees. I am personally not going to hire just anyone that shows up with a gun as a security guard. There will be a lot of supply of unskilled and semi-skilled labor and not much demand.

I don't think that even highly skilled people like doctors and nurses would be in that great of a position. Our modern medical system sucks up a lot of skilled people to care for the chronically and acutely ill people who will die off pretty quickly if things get really bad, leaving a large overhanging supply of skilled medical people with little to do.