I just found 50+ plastic arrow nocks in my father's archery stash from the 80's. Every arrow I have ever made I have made self nocks, and I am sure that will continue, so they are available for a trade. Make me an offer of what you think they are worth, although I could use a good arrowhead notching tool. The one I made for myself is not very good.
I am also in the market for some snake skins--but I don't know what people who have them want for them. I would assume skins would be worth more than old plastic nocks, so we are probably talking about two different trades here. I do have obsidian, and my arrow points from it are getting much better. I can also make arrows, if you are interested.