With our move and all I have sold a plethora of items on eBay over the last few years. Yes, they charge quite a bit as a sellers fee, however it does allow you to gain access to the entire Country in one easy step. They also do give some support if you get a bad buyer.
Am I happy about giving up 20% - no! That said, I have cleaned out and gotten rid of plenty of unwanted or unneeded stuff I had cluttering things up. 20% seems to be about the norm as a commission in gun shops as well. At the point of getting paid for sold items, it's all "found money" and I am glad to gain the clean space in our closets and shelves.